diff --git a/.env.example b/.env.example
index f8dadb4..efa2617 100644
--- a/.env.example
+++ b/.env.example
@@ -40,6 +40,37 @@
 # Leave empty to auto-generate and persist to save.json
 # OVERLORD_AGENT_TOKEN=
 
+# ============================================
+# OPTIONAL: OIDC / SSO login
+# ============================================
+# Generic OIDC works with providers such as Authentik, Authelia, Keycloak, Zitadel, and Dex.
+# Configure your provider callback/redirect URI as:
+#   https://YOUR_OVERLORD_HOST/api/oidc/callback
+# Keep local username/password login enabled as a fallback.
+# OVERLORD_OIDC_ENABLED=true
+# OVERLORD_OIDC_LABEL=Sign in with SSO
+# OVERLORD_OIDC_ISSUER=https://auth.example.com/application/o/overlord/
+# OVERLORD_OIDC_CLIENT_ID=overlord
+# OVERLORD_OIDC_CLIENT_SECRET=change-me
+# OVERLORD_OIDC_REDIRECT_URI=https://overlord.example.com/api/oidc/callback
+# OVERLORD_OIDC_DEFAULT_ROLE=viewer
+# OVERLORD_OIDC_ALLOWED_DOMAINS=example.com
+# OVERLORD_OIDC_ADMIN_GROUPS=overlord-admins
+# OVERLORD_OIDC_OPERATOR_GROUPS=overlord-operators
+# OVERLORD_OIDC_VIEWER_GROUPS=overlord-viewers
+
+# ============================================
+# OPTIONAL: Login screen branding
+# ============================================
+# Use a logo URL, or leave it empty and set a Font Awesome icon class.
+# Logo URLs may be absolute http(s) URLs or root-relative paths such as /assets/logo.png.
+# OVERLORD_LOGIN_BRAND_NAME=Acme SOC
+# OVERLORD_LOGIN_TITLE=Welcome to Acme Overlord
+# OVERLORD_LOGIN_SUBTITLE=Sign in with your Acme identity
+# OVERLORD_LOGIN_LOGO_URL=/assets/acme-logo.png
+# OVERLORD_LOGIN_LOGO_ALT=Acme logo
+# OVERLORD_LOGIN_ICON_CLASS=fa-solid fa-shield-halved
+
 # ============================================
 # ADVANCED: Custom TLS certificates
 # ============================================
diff --git a/Overlord-Server/public/assets/login.js b/Overlord-Server/public/assets/login.js
index 6caff3f..927354b 100644
--- a/Overlord-Server/public/assets/login.js
+++ b/Overlord-Server/public/assets/login.js
@@ -4,6 +4,52 @@ const pass = document.getElementById("pass");
 const mfaGroup = document.getElementById("mfa-group");
 const mfaCode = document.getElementById("mfa-code");
 const errEl = document.getElementById("error");
+const oidcLogin = document.getElementById("oidc-login");
+const oidcLoginLabel = document.getElementById("oidc-login-label");
+const loginBrand = document.getElementById("login-brand");
+const loginTitle = document.getElementById("login-title");
+const loginSubtitle = document.getElementById("login-subtitle");
+const loginIcon = document.getElementById("login-icon");
+const loginLogo = document.getElementById("login-logo");
+
+(() => {
+  const params = new URLSearchParams(window.location.search);
+  const oidcError = params.get("oidc_error");
+  if (oidcError) {
+    errEl.textContent = oidcError;
+    window.history.replaceState({}, document.title, "/login.html");
+  }
+})();
+
+(async () => {
+  try {
+    const res = await fetch("/api/login/branding");
+    if (!res.ok) return;
+    const data = await res.json();
+
+    if (loginBrand && data.productName) loginBrand.textContent = data.productName;
+    if (loginTitle && data.title) loginTitle.textContent = data.title;
+    if (loginSubtitle && data.subtitle) loginSubtitle.textContent = data.subtitle;
+    if (data.productName) document.title = `${data.productName} Login`;
+
+    if (loginIcon && data.iconClass) {
+      loginIcon.className = `${data.iconClass} login-crown`;
+    }
+
+    if (loginLogo && loginIcon && data.logoUrl) {
+      loginLogo.alt = data.logoAlt || `${data.productName || "Overlord"} logo`;
+      loginLogo.onload = () => {
+        loginLogo.style.display = "";
+        loginIcon.style.display = "none";
+      };
+      loginLogo.onerror = () => {
+        loginLogo.style.display = "none";
+        loginIcon.style.display = "";
+      };
+      loginLogo.src = data.logoUrl;
+    }
+  } catch {}
+})();
 
 (async () => {
   try {
@@ -16,6 +62,19 @@ const errEl = document.getElementById("error");
   } catch {}
 })();
 
+(async () => {
+  try {
+    const res = await fetch("/api/oidc/status");
+    if (!res.ok) return;
+    const data = await res.json();
+    if (data.enabled && data.loginUrl && oidcLogin) {
+      oidcLogin.href = data.loginUrl;
+      if (oidcLoginLabel && data.label) oidcLoginLabel.textContent = data.label;
+      oidcLogin.style.display = "";
+    }
+  } catch {}
+})();
+
 if (typeof anime !== "undefined") {
   const particles = document.querySelectorAll(".particle");
   particles.forEach((particle, i) => {
diff --git a/Overlord-Server/public/assets/main.css b/Overlord-Server/public/assets/main.css
index 475ed22..5278126 100644
--- a/Overlord-Server/public/assets/main.css
+++ b/Overlord-Server/public/assets/main.css
@@ -1060,6 +1060,14 @@ article.card[data-bookmarked="true"] {
   filter: drop-shadow(0 4px 12px rgba(122, 91, 255, 0.5));
 }
 
+.login-logo {
+  width: 56px;
+  height: 56px;
+  object-fit: contain;
+  border-radius: 12px;
+  filter: drop-shadow(0 4px 12px rgba(122, 91, 255, 0.35));
+}
+
 .login-brand {
   text-align: center;
   font-size: 28px;
diff --git a/Overlord-Server/public/assets/settings.js b/Overlord-Server/public/assets/settings.js
index 5f09009..2325792 100644
--- a/Overlord-Server/public/assets/settings.js
+++ b/Overlord-Server/public/assets/settings.js
@@ -82,6 +82,28 @@ const tlsCertbotCertFileInput = document.getElementById("tls-certbot-cert-file")
 const tlsCertbotKeyFileInput = document.getElementById("tls-certbot-key-file");
 const tlsCertbotCaFileInput = document.getElementById("tls-certbot-ca-file");
 
+const oidcForm = document.getElementById("oidc-form");
+const oidcPermissionNote = document.getElementById("oidc-permission-note");
+const oidcSaveBtn = document.getElementById("oidc-save-btn");
+const oidcEnabledInput = document.getElementById("oidc-enabled");
+const oidcLabelInput = document.getElementById("oidc-label");
+const oidcIssuerInput = document.getElementById("oidc-issuer");
+const oidcClientIdInput = document.getElementById("oidc-client-id");
+const oidcClientSecretInput = document.getElementById("oidc-client-secret");
+const oidcSecretHint = document.getElementById("oidc-secret-hint");
+const oidcRedirectUriInput = document.getElementById("oidc-redirect-uri");
+const oidcScopesInput = document.getElementById("oidc-scopes");
+const oidcClientAuthMethodInput = document.getElementById("oidc-client-auth-method");
+const oidcAutoProvisionInput = document.getElementById("oidc-auto-provision");
+const oidcAllowEmailLinkInput = document.getElementById("oidc-allow-email-link");
+const oidcDefaultRoleInput = document.getElementById("oidc-default-role");
+const oidcAllowedDomainsInput = document.getElementById("oidc-allowed-domains");
+const oidcAllowedEmailsInput = document.getElementById("oidc-allowed-emails");
+const oidcGroupClaimInput = document.getElementById("oidc-group-claim");
+const oidcAdminGroupsInput = document.getElementById("oidc-admin-groups");
+const oidcOperatorGroupsInput = document.getElementById("oidc-operator-groups");
+const oidcViewerGroupsInput = document.getElementById("oidc-viewer-groups");
+
 const appearanceForm = document.getElementById("appearance-form");
 const appearancePermissionNote = document.getElementById("appearance-permission-note");
 const appearanceSaveBtn = document.getElementById("appearance-save-btn");
@@ -99,6 +121,7 @@ const wipeOfflineMessage = document.getElementById("wipe-offline-message");
 let currentUser = null;
 let securityConfig = null;
 let tlsConfig = null;
+let oidcConfig = null;
 
 function showMessage(text, type = "ok") {
   if (!messageEl) return;
@@ -212,6 +235,7 @@ async function renderPermissionsOverview() {
       perms: [
         "system:security",
         "system:tls",
+        "system:oidc",
         "system:registration",
         "system:notifications",
         "system:chat",
@@ -425,6 +449,94 @@ async function loadTlsSettings() {
   setTlsFormDisabled(false);
 }
 
+function listToCsv(value) {
+  return Array.isArray(value) ? value.join(", ") : "";
+}
+
+function csvToList(value) {
+  return String(value || "")
+    .split(",")
+    .map((item) => item.trim())
+    .filter(Boolean);
+}
+
+function setOidcFormDisabled(disabled) {
+  const controls = [
+    oidcEnabledInput,
+    oidcLabelInput,
+    oidcIssuerInput,
+    oidcClientIdInput,
+    oidcClientSecretInput,
+    oidcRedirectUriInput,
+    oidcScopesInput,
+    oidcClientAuthMethodInput,
+    oidcAutoProvisionInput,
+    oidcAllowEmailLinkInput,
+    oidcDefaultRoleInput,
+    oidcAllowedDomainsInput,
+    oidcAllowedEmailsInput,
+    oidcGroupClaimInput,
+    oidcAdminGroupsInput,
+    oidcOperatorGroupsInput,
+    oidcViewerGroupsInput,
+    oidcSaveBtn,
+  ];
+
+  for (const control of controls) {
+    if (!control) continue;
+    control.disabled = disabled;
+  }
+}
+
+function applyOidcForm() {
+  const cfg = oidcConfig || {};
+  if (oidcEnabledInput) oidcEnabledInput.checked = Boolean(cfg.enabled);
+  if (oidcLabelInput) oidcLabelInput.value = cfg.label || "Single sign-on";
+  if (oidcIssuerInput) oidcIssuerInput.value = cfg.issuer || "";
+  if (oidcClientIdInput) oidcClientIdInput.value = cfg.clientId || "";
+  if (oidcClientSecretInput) oidcClientSecretInput.value = "";
+  if (oidcSecretHint) {
+    oidcSecretHint.textContent = cfg.clientSecretSet
+      ? "A client secret is saved. Leave this blank to keep it."
+      : "No client secret is currently saved.";
+  }
+  if (oidcRedirectUriInput) oidcRedirectUriInput.value = cfg.redirectUri || "";
+  if (oidcScopesInput) oidcScopesInput.value = listToCsv(cfg.scopes || ["openid", "profile", "email"]);
+  if (oidcClientAuthMethodInput) oidcClientAuthMethodInput.value = cfg.clientAuthMethod || "client_secret_post";
+  if (oidcAutoProvisionInput) oidcAutoProvisionInput.checked = cfg.autoProvision !== false;
+  if (oidcAllowEmailLinkInput) oidcAllowEmailLinkInput.checked = Boolean(cfg.allowEmailLink);
+  if (oidcDefaultRoleInput) oidcDefaultRoleInput.value = cfg.defaultRole || "viewer";
+  if (oidcAllowedDomainsInput) oidcAllowedDomainsInput.value = listToCsv(cfg.allowedDomains);
+  if (oidcAllowedEmailsInput) oidcAllowedEmailsInput.value = listToCsv(cfg.allowedEmails);
+  if (oidcGroupClaimInput) oidcGroupClaimInput.value = cfg.groupClaim || "groups";
+  if (oidcAdminGroupsInput) oidcAdminGroupsInput.value = listToCsv(cfg.adminGroups);
+  if (oidcOperatorGroupsInput) oidcOperatorGroupsInput.value = listToCsv(cfg.operatorGroups);
+  if (oidcViewerGroupsInput) oidcViewerGroupsInput.value = listToCsv(cfg.viewerGroups);
+}
+
+async function loadOidcSettings() {
+  if (!currentUser) return;
+
+  if (!userHas("system:oidc")) {
+    if (oidcPermissionNote) oidcPermissionNote.classList.remove("hidden");
+    setOidcFormDisabled(true);
+    return;
+  }
+
+  if (oidcPermissionNote) oidcPermissionNote.classList.add("hidden");
+  const res = await fetch("/api/settings/oidc", { credentials: "include" });
+  if (!res.ok) {
+    showMessage("Failed to load OIDC settings.", "error");
+    setOidcFormDisabled(true);
+    return;
+  }
+
+  const data = await res.json().catch(() => ({}));
+  oidcConfig = data.oidc || null;
+  applyOidcForm();
+  setOidcFormDisabled(false);
+}
+
 function updateNavLayoutButtons(mode, sidebarBtn, topbarBtn) {
   const active = ["bg-indigo-600/80", "border-indigo-500", "text-white"];
   const inactive = ["bg-slate-800", "border-slate-700", "text-slate-400", "hover:bg-slate-700", "hover:text-slate-200"];
@@ -723,6 +835,82 @@ async function saveTlsSettings(event) {
   showMessage("TLS settings updated. Restart server to apply.");
 }
 
+async function saveOidcSettings(event) {
+  event.preventDefault();
+  if (!requireUiPermission("system:oidc", "OIDC settings permission required.")) {
+    return;
+  }
+
+  const payload = {
+    enabled: !!oidcEnabledInput?.checked,
+    label: String(oidcLabelInput?.value || "").trim(),
+    issuer: String(oidcIssuerInput?.value || "").trim(),
+    clientId: String(oidcClientIdInput?.value || "").trim(),
+    redirectUri: String(oidcRedirectUriInput?.value || "").trim(),
+    scopes: csvToList(oidcScopesInput?.value),
+    clientAuthMethod: oidcClientAuthMethodInput?.value || "client_secret_post",
+    autoProvision: !!oidcAutoProvisionInput?.checked,
+    allowEmailLink: !!oidcAllowEmailLinkInput?.checked,
+    defaultRole: oidcDefaultRoleInput?.value || "viewer",
+    allowedDomains: csvToList(oidcAllowedDomainsInput?.value),
+    allowedEmails: csvToList(oidcAllowedEmailsInput?.value),
+    groupClaim: String(oidcGroupClaimInput?.value || "").trim(),
+    adminGroups: csvToList(oidcAdminGroupsInput?.value),
+    operatorGroups: csvToList(oidcOperatorGroupsInput?.value),
+    viewerGroups: csvToList(oidcViewerGroupsInput?.value),
+  };
+
+  const clientSecret = String(oidcClientSecretInput?.value || "");
+  if (clientSecret) {
+    payload.clientSecret = clientSecret;
+  }
+
+  if (payload.enabled) {
+    if (!payload.issuer) {
+      showMessage("OIDC issuer URL is required when OIDC is enabled.", "error");
+      oidcIssuerInput?.focus();
+      return;
+    }
+    if (!payload.redirectUri) {
+      showMessage("OIDC redirect URI is required when OIDC is enabled.", "error");
+      oidcRedirectUriInput?.focus();
+      return;
+    }
+    if (!payload.clientId) {
+      showMessage("OIDC client ID is required when OIDC is enabled.", "error");
+      oidcClientIdInput?.focus();
+      return;
+    }
+    if (!payload.scopes.length || !payload.scopes.includes("openid")) {
+      showMessage("OIDC scopes must include openid.", "error");
+      oidcScopesInput?.focus();
+      return;
+    }
+    if (payload.clientAuthMethod !== "none" && !clientSecret && !oidcConfig?.clientSecretSet) {
+      showMessage("OIDC client secret is required for the selected client auth method.", "error");
+      oidcClientSecretInput?.focus();
+      return;
+    }
+  }
+
+  const res = await fetch("/api/settings/oidc", {
+    method: "PUT",
+    headers: { "Content-Type": "application/json" },
+    credentials: "include",
+    body: JSON.stringify(payload),
+  });
+
+  const data = await res.json().catch(() => ({}));
+  if (!res.ok) {
+    showMessage(data.error || "Failed to save OIDC settings.", "error");
+    return;
+  }
+
+  oidcConfig = data.oidc || payload;
+  applyOidcForm();
+  showMessage("OIDC settings saved. Environment variables still take priority after restart.");
+}
+
 async function runCertbotAutoSetup() {
   if (!requireUiPermission("system:tls", "TLS settings permission required.")) {
     return;
@@ -1448,6 +1636,7 @@ async function importSettings(event) {
 
     await loadSecurityPolicy();
     await loadTlsSettings();
+    await loadOidcSettings();
     await loadAppearanceSettings();
   } catch (error) {
     showExportImportMessage(`Import failed: ${String(error?.message || error)}`, "error");
@@ -2429,6 +2618,7 @@ async function init() {
     securityForm.addEventListener("submit", saveSecurityPolicy);
     tlsForm.addEventListener("submit", saveTlsSettings);
     tlsCertbotAutoBtn.addEventListener("click", runCertbotAutoSetup);
+    if (oidcForm) oidcForm.addEventListener("submit", saveOidcSettings);
     if (appearanceForm) appearanceForm.addEventListener("submit", saveAppearanceSettings);
     if (chatSettingsForm) chatSettingsForm.addEventListener("submit", saveChatSettings);
     if (inputArchiveUserForm) inputArchiveUserForm.addEventListener("submit", saveInputArchivePreference);
diff --git a/Overlord-Server/public/login.html b/Overlord-Server/public/login.html
index d160579..bac245a 100644
--- a/Overlord-Server/public/login.html
+++ b/Overlord-Server/public/login.html
@@ -23,11 +23,12 @@
     </div>
     <div class="login-card">
       <div class="login-crown-wrapper">
-        <i class="fa-solid fa-crown login-crown"></i>
+        <img id="login-logo" class="login-logo" alt="Overlord logo" style="display: none" />
+        <i id="login-icon" class="fa-solid fa-crown login-crown"></i>
       </div>
-      <div class="brand login-brand">Overlord</div>
-      <h2 class="login-title">Welcome back</h2>
-      <p class="muted login-subtitle">Sign in to your control plane</p>
+      <div id="login-brand" class="brand login-brand">Overlord</div>
+      <h2 id="login-title" class="login-title">Welcome back</h2>
+      <p id="login-subtitle" class="muted login-subtitle">Sign in to your control plane</p>
       <form id="login-form">
         <div class="form-group">
           <label class="label">Username</label>
@@ -79,6 +80,10 @@
         </button>
         <div id="error" class="error" aria-live="polite"></div>
       </form>
+      <a id="oidc-login" href="/api/oidc/login" class="button secondary full login-btn" style="display: none; margin-top: 0.75rem">
+        <span id="oidc-login-label">Single sign-on</span>
+        <i class="fa-solid fa-right-to-bracket btn-icon"></i>
+      </a>
       <div id="register-link" class="login-footer" style="display: none">
         Don't have an account?
         <a href="/register.html">Create one</a>
diff --git a/Overlord-Server/public/settings.html b/Overlord-Server/public/settings.html
index e8ddf88..2df83a3 100644
--- a/Overlord-Server/public/settings.html
+++ b/Overlord-Server/public/settings.html
@@ -94,6 +94,7 @@
             <a data-target="section-permissions-overview" class="settings-nav-link" data-permission="users:manage" style="--accent: 167 139 250"><i class="fa-solid fa-user-shield w-4 text-violet-400"></i><span>Access Overview</span></a>
             <a data-target="section-security"         class="settings-nav-link" data-permission="system:security" style="--accent: 129 140 248"><i class="fa-solid fa-shield-halved w-4 text-indigo-400"></i><span>Security Policy</span></a>
             <a data-target="section-tls"              class="settings-nav-link" data-permission="system:tls" style="--accent: 34 211 238"><i class="fa-solid fa-certificate w-4 text-cyan-400"></i><span>TLS Certificates</span></a>
+            <a data-target="section-oidc"             class="settings-nav-link" data-permission="system:oidc" style="--accent: 20 184 166"><i class="fa-solid fa-right-to-bracket w-4 text-teal-400"></i><span>OIDC / SSO</span></a>
             <a data-target="chat-settings-section"    class="settings-nav-link" data-permission="system:chat" style="--accent: 56 189 248"><i class="fa-solid fa-comments w-4 text-sky-400"></i><span>Team Chat</span></a>
             <a data-target="registration-section"     class="settings-nav-link" data-permission="system:registration" style="--accent: 52 211 153"><i class="fa-solid fa-user-plus w-4 text-emerald-400"></i><span>Registration</span></a>
             <a data-target="thumbnails-section"       class="settings-nav-link" data-permission="system:thumbnails" style="--accent: 56 189 248"><i class="fa-solid fa-images w-4 text-sky-400"></i><span>Screenshot Thumbnails</span></a>
@@ -828,6 +829,137 @@
         </form>
       </section>
 
+      <!-- OIDC / SSO -->
+      <section id="section-oidc" data-permission="system:oidc" class="hidden bg-slate-900/60 border border-slate-800 rounded-xl p-5 space-y-4 settings-section">
+        <div class="flex items-center gap-3">
+          <div class="flex items-center justify-center w-9 h-9 rounded-lg bg-teal-500/10 border border-teal-500/30">
+            <i class="fa-solid fa-right-to-bracket text-teal-400"></i>
+          </div>
+          <div>
+            <h2 class="text-lg font-semibold">OIDC / SSO</h2>
+            <p class="text-sm text-slate-400">Configure generic OIDC login for self-hosted identity providers.</p>
+          </div>
+        </div>
+
+        <form id="oidc-form" class="space-y-4">
+          <div id="oidc-permission-note" class="hidden rounded-lg border border-amber-800 bg-amber-900/20 text-amber-200 px-3 py-2 text-sm">
+            Your permissions do not allow OIDC setting changes.
+          </div>
+
+          <label class="flex items-center gap-2 text-sm">
+            <input id="oidc-enabled" type="checkbox" class="h-4 w-4 accent-teal-500" />
+            <span>Enable OIDC login button</span>
+          </label>
+
+          <div class="grid grid-cols-1 md:grid-cols-2 gap-3">
+            <label class="block">
+              <span class="text-sm text-slate-300">Login button label</span>
+              <input id="oidc-label" type="text" placeholder="Sign in with SSO" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+            <label class="block">
+              <span class="text-sm text-slate-300">Default role for new users</span>
+              <select id="oidc-default-role" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500">
+                <option value="viewer">Viewer</option>
+                <option value="operator">Operator</option>
+                <option value="admin">Admin</option>
+              </select>
+            </label>
+          </div>
+
+          <div class="grid grid-cols-1 gap-3">
+            <label class="block">
+              <span class="text-sm text-slate-300">Issuer URL <span class="text-rose-400" aria-hidden="true">*</span><span class="sr-only">required</span></span>
+              <input id="oidc-issuer" type="url" placeholder="https://auth.example.com/application/o/overlord/" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+            <label class="block">
+              <span class="text-sm text-slate-300">Redirect URI <span class="text-rose-400" aria-hidden="true">*</span><span class="sr-only">required</span></span>
+              <input id="oidc-redirect-uri" type="url" placeholder="https://overlord.example.com/api/oidc/callback" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+          </div>
+
+          <div class="grid grid-cols-1 md:grid-cols-2 gap-3">
+            <label class="block">
+              <span class="text-sm text-slate-300">Client ID <span class="text-rose-400" aria-hidden="true">*</span><span class="sr-only">required</span></span>
+              <input id="oidc-client-id" type="text" autocomplete="off" placeholder="overlord" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+            <label class="block">
+              <span class="text-sm text-slate-300">Client secret <span class="text-rose-400" aria-hidden="true">*</span><span class="sr-only">required unless client auth method is none</span></span>
+              <input id="oidc-client-secret" type="password" autocomplete="new-password" placeholder="Leave blank to keep existing secret" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+              <p id="oidc-secret-hint" class="text-xs text-slate-500 mt-1">No client secret is currently saved.</p>
+            </label>
+          </div>
+
+          <div class="grid grid-cols-1 md:grid-cols-2 gap-3">
+            <label class="block">
+              <span class="text-sm text-slate-300">Scopes <span class="text-rose-400" aria-hidden="true">*</span><span class="sr-only">required</span></span>
+              <input id="oidc-scopes" type="text" placeholder="openid, profile, email" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+            <label class="block">
+              <span class="text-sm text-slate-300">Client auth method</span>
+              <select id="oidc-client-auth-method" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500">
+                <option value="client_secret_post">Client secret POST</option>
+                <option value="client_secret_basic">Client secret basic</option>
+                <option value="none">None / PKCE only</option>
+              </select>
+            </label>
+          </div>
+
+          <div class="grid grid-cols-1 md:grid-cols-2 gap-3">
+            <label class="flex items-start gap-2 rounded-lg border border-slate-800 bg-slate-900 px-3 py-3 text-sm">
+              <input id="oidc-auto-provision" type="checkbox" class="mt-1 h-4 w-4 accent-teal-500" />
+              <span>
+                <span class="block text-slate-200">Auto-provision allowed users</span>
+                <span class="block text-xs text-slate-500">Create local users after a successful provider login.</span>
+              </span>
+            </label>
+            <label class="flex items-start gap-2 rounded-lg border border-slate-800 bg-slate-900 px-3 py-3 text-sm">
+              <input id="oidc-allow-email-link" type="checkbox" class="mt-1 h-4 w-4 accent-teal-500" />
+              <span>
+                <span class="block text-slate-200">Allow email linking</span>
+                <span class="block text-xs text-slate-500">Link to existing users only when you trust verified email claims.</span>
+              </span>
+            </label>
+          </div>
+
+          <div class="grid grid-cols-1 md:grid-cols-2 gap-3">
+            <label class="block">
+              <span class="text-sm text-slate-300">Allowed email domains</span>
+              <input id="oidc-allowed-domains" type="text" placeholder="example.com, example.org" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+            <label class="block">
+              <span class="text-sm text-slate-300">Allowed email addresses</span>
+              <input id="oidc-allowed-emails" type="text" placeholder="admin@example.com" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+            </label>
+          </div>
+
+          <div class="rounded-lg border border-slate-800 bg-slate-950/40 p-4 space-y-3">
+            <p class="text-xs font-semibold uppercase tracking-wider text-slate-500">Group Role Mapping</p>
+            <div class="grid grid-cols-1 md:grid-cols-2 gap-3">
+              <label class="block">
+                <span class="text-sm text-slate-300">Group claim</span>
+                <input id="oidc-group-claim" type="text" placeholder="groups" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+              </label>
+              <label class="block">
+                <span class="text-sm text-slate-300">Admin groups</span>
+                <input id="oidc-admin-groups" type="text" placeholder="overlord-admins" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+              </label>
+              <label class="block">
+                <span class="text-sm text-slate-300">Operator groups</span>
+                <input id="oidc-operator-groups" type="text" placeholder="overlord-operators" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+              </label>
+              <label class="block">
+                <span class="text-sm text-slate-300">Viewer groups</span>
+                <input id="oidc-viewer-groups" type="text" placeholder="overlord-viewers" class="mt-1 w-full px-3 py-2 rounded-lg bg-slate-900 border border-slate-700 focus:outline-none focus:ring-2 focus:ring-teal-500" />
+              </label>
+            </div>
+          </div>
+
+          <button type="submit" id="oidc-save-btn" class="inline-flex items-center gap-2 px-4 py-2 rounded-lg bg-teal-700 hover:bg-teal-600 transition-colors text-white text-sm font-medium">
+            <i class="fa-solid fa-floppy-disk"></i>Save OIDC Settings
+          </button>
+        </form>
+      </section>
+
       <!-- Team Chat -->
       <section id="chat-settings-section" data-permission="system:chat" class="hidden bg-slate-900/60 border border-slate-800 rounded-xl p-5 space-y-4 settings-section">
         <div class="flex items-center gap-3">
diff --git a/Overlord-Server/src/auth.test.ts b/Overlord-Server/src/auth.test.ts
index 9312270..341c73a 100644
--- a/Overlord-Server/src/auth.test.ts
+++ b/Overlord-Server/src/auth.test.ts
@@ -31,6 +31,19 @@ describe("auth token extraction", () => {
   });
 });
 
+describe("login branding", () => {
+  test("returns default public login branding", async () => {
+    const url = new URL("https://localhost/api/login/branding");
+    const res = await handleAuthRoutes(new Request(url), url, mockServer);
+    expect(res?.status).toBe(200);
+
+    const body = (await res!.json()) as any;
+    expect(body.productName).toBe("Overlord");
+    expect(body.title).toBe("Welcome back");
+    expect(body.logoUrl).toBe("");
+  });
+});
+
 describe("auth MFA login", () => {
   test("MFA-enabled user gets a challenge and can login with TOTP", async () => {
     const username = `mfa_user_${Date.now().toString(36)}`;
diff --git a/Overlord-Server/src/config.ts b/Overlord-Server/src/config.ts
index baff91d..d5646b4 100644
--- a/Overlord-Server/src/config.ts
+++ b/Overlord-Server/src/config.ts
@@ -12,6 +12,25 @@ export interface Config {
     jwtSecret: string;
     agentToken: string;
   };
+  oidc: {
+    enabled: boolean;
+    label: string;
+    issuer: string;
+    clientId: string;
+    clientSecret: string;
+    redirectUri: string;
+    scopes: string[];
+    clientAuthMethod: "client_secret_post" | "client_secret_basic" | "none";
+    autoProvision: boolean;
+    allowEmailLink: boolean;
+    defaultRole: "admin" | "operator" | "viewer";
+    allowedEmails: string[];
+    allowedDomains: string[];
+    groupClaim: string;
+    adminGroups: string[];
+    operatorGroups: string[];
+    viewerGroups: string[];
+  };
   server: {
     port: number;
     host: string;
@@ -64,6 +83,14 @@ export interface Config {
   };
   appearance: {
     customCSS: string;
+    loginBranding: {
+      productName: string;
+      title: string;
+      subtitle: string;
+      iconClass: string;
+      logoUrl: string;
+      logoAlt: string;
+    };
   };
   plugins: {
     trustedKeys: string[];
@@ -105,6 +132,25 @@ const DEFAULT_CONFIG: Config = {
     jwtSecret: "",
     agentToken: "",
   },
+  oidc: {
+    enabled: false,
+    label: "Single sign-on",
+    issuer: "",
+    clientId: "",
+    clientSecret: "",
+    redirectUri: "",
+    scopes: ["openid", "profile", "email"],
+    clientAuthMethod: "client_secret_post",
+    autoProvision: true,
+    allowEmailLink: false,
+    defaultRole: "viewer",
+    allowedEmails: [],
+    allowedDomains: [],
+    groupClaim: "groups",
+    adminGroups: [],
+    operatorGroups: [],
+    viewerGroups: [],
+  },
   server: {
     port: 5173,
     host: "0.0.0.0",
@@ -157,6 +203,14 @@ const DEFAULT_CONFIG: Config = {
   },
   appearance: {
     customCSS: "",
+    loginBranding: {
+      productName: "Overlord",
+      title: "Welcome back",
+      subtitle: "Sign in to your control plane",
+      iconClass: "fa-solid fa-crown",
+      logoUrl: "",
+      logoAlt: "Overlord logo",
+    },
   },
   plugins: {
     trustedKeys: [],
@@ -198,6 +252,73 @@ function envBoolOverride(name: string): boolean | undefined {
   return undefined;
 }
 
+function splitList(value: unknown): string[] {
+  if (Array.isArray(value)) {
+    return value.map((v) => String(v).trim()).filter(Boolean);
+  }
+  if (typeof value === "string") {
+    return value.split(",").map((v) => v.trim()).filter(Boolean);
+  }
+  return [];
+}
+
+function pickRole(value: unknown, fallback: Config["oidc"]["defaultRole"]): Config["oidc"]["defaultRole"] {
+  return value === "admin" || value === "operator" || value === "viewer"
+    ? value
+    : fallback;
+}
+
+function pickClientAuthMethod(value: unknown): Config["oidc"]["clientAuthMethod"] {
+  return value === "client_secret_basic" || value === "none"
+    ? value
+    : "client_secret_post";
+}
+
+function cleanText(value: unknown, fallback: string, maxLength: number): string {
+  const raw = typeof value === "string" ? value : "";
+  const cleaned = raw
+    .replace(/[\u0000-\u001f\u007f]/g, " ")
+    .replace(/\s+/g, " ")
+    .trim();
+  return (cleaned || fallback).slice(0, maxLength);
+}
+
+function cleanIconClass(value: unknown, fallback: string): string {
+  const raw = cleanText(value, fallback, 120);
+  const cleaned = raw.replace(/[^A-Za-z0-9_:\-\s]/g, "").replace(/\s+/g, " ").trim();
+  return cleaned || fallback;
+}
+
+function cleanLogoUrl(value: unknown): string {
+  const raw = cleanText(value, "", 2048);
+  if (!raw) return "";
+  if (raw.startsWith("/") && !raw.startsWith("//")) return raw;
+
+  try {
+    const parsed = new URL(raw);
+    if (parsed.protocol === "https:" || parsed.protocol === "http:") {
+      return parsed.toString();
+    }
+  } catch {}
+
+  return "";
+}
+
+function cleanLoginBranding(
+  value: Partial<Config["appearance"]["loginBranding"]> | undefined,
+  fallback: Config["appearance"]["loginBranding"],
+): Config["appearance"]["loginBranding"] {
+  const productName = cleanText(value?.productName, fallback.productName, 80);
+  return {
+    productName,
+    title: cleanText(value?.title, fallback.title, 120),
+    subtitle: cleanText(value?.subtitle, fallback.subtitle, 180),
+    iconClass: cleanIconClass(value?.iconClass, fallback.iconClass),
+    logoUrl: cleanLogoUrl(value?.logoUrl),
+    logoAlt: cleanText(value?.logoAlt, `${productName} logo`, 120),
+  };
+}
+
 type SaveSecrets = {
   auth?: {
     jwtSecret?: string;
@@ -393,6 +514,82 @@ export function loadConfig(): Config {
       jwtSecret: finalJwtSecret,
       agentToken: finalAgentToken,
     },
+    oidc: {
+      enabled:
+        envBoolOverride("OVERLORD_OIDC_ENABLED") ??
+        (fileConfig.oidc?.enabled !== undefined
+          ? Boolean(fileConfig.oidc.enabled)
+          : DEFAULT_CONFIG.oidc.enabled),
+      label:
+        process.env.OVERLORD_OIDC_LABEL ||
+        fileConfig.oidc?.label ||
+        DEFAULT_CONFIG.oidc.label,
+      issuer:
+        process.env.OVERLORD_OIDC_ISSUER ||
+        fileConfig.oidc?.issuer ||
+        DEFAULT_CONFIG.oidc.issuer,
+      clientId:
+        process.env.OVERLORD_OIDC_CLIENT_ID ||
+        fileConfig.oidc?.clientId ||
+        DEFAULT_CONFIG.oidc.clientId,
+      clientSecret:
+        process.env.OVERLORD_OIDC_CLIENT_SECRET ||
+        fileConfig.oidc?.clientSecret ||
+        DEFAULT_CONFIG.oidc.clientSecret,
+      redirectUri:
+        process.env.OVERLORD_OIDC_REDIRECT_URI ||
+        fileConfig.oidc?.redirectUri ||
+        DEFAULT_CONFIG.oidc.redirectUri,
+      scopes: (() => {
+        const envScopes = splitList(process.env.OVERLORD_OIDC_SCOPES);
+        if (envScopes.length > 0) return envScopes;
+        const fileScopes = splitList(fileConfig.oidc?.scopes);
+        return fileScopes.length > 0 ? fileScopes : [...DEFAULT_CONFIG.oidc.scopes];
+      })(),
+      clientAuthMethod: pickClientAuthMethod(
+        process.env.OVERLORD_OIDC_CLIENT_AUTH_METHOD ||
+        fileConfig.oidc?.clientAuthMethod,
+      ),
+      autoProvision:
+        envBoolOverride("OVERLORD_OIDC_AUTO_PROVISION") ??
+        (fileConfig.oidc?.autoProvision !== undefined
+          ? Boolean(fileConfig.oidc.autoProvision)
+          : DEFAULT_CONFIG.oidc.autoProvision),
+      allowEmailLink:
+        envBoolOverride("OVERLORD_OIDC_ALLOW_EMAIL_LINK") ??
+        (fileConfig.oidc?.allowEmailLink !== undefined
+          ? Boolean(fileConfig.oidc.allowEmailLink)
+          : DEFAULT_CONFIG.oidc.allowEmailLink),
+      defaultRole: pickRole(
+        process.env.OVERLORD_OIDC_DEFAULT_ROLE ||
+        fileConfig.oidc?.defaultRole,
+        DEFAULT_CONFIG.oidc.defaultRole,
+      ),
+      allowedEmails: (() => {
+        const envEmails = splitList(process.env.OVERLORD_OIDC_ALLOWED_EMAILS);
+        return envEmails.length > 0 ? envEmails : splitList(fileConfig.oidc?.allowedEmails);
+      })(),
+      allowedDomains: (() => {
+        const envDomains = splitList(process.env.OVERLORD_OIDC_ALLOWED_DOMAINS);
+        return envDomains.length > 0 ? envDomains : splitList(fileConfig.oidc?.allowedDomains);
+      })(),
+      groupClaim:
+        process.env.OVERLORD_OIDC_GROUP_CLAIM ||
+        fileConfig.oidc?.groupClaim ||
+        DEFAULT_CONFIG.oidc.groupClaim,
+      adminGroups: (() => {
+        const envGroups = splitList(process.env.OVERLORD_OIDC_ADMIN_GROUPS);
+        return envGroups.length > 0 ? envGroups : splitList(fileConfig.oidc?.adminGroups);
+      })(),
+      operatorGroups: (() => {
+        const envGroups = splitList(process.env.OVERLORD_OIDC_OPERATOR_GROUPS);
+        return envGroups.length > 0 ? envGroups : splitList(fileConfig.oidc?.operatorGroups);
+      })(),
+      viewerGroups: (() => {
+        const envGroups = splitList(process.env.OVERLORD_OIDC_VIEWER_GROUPS);
+        return envGroups.length > 0 ? envGroups : splitList(fileConfig.oidc?.viewerGroups);
+      })(),
+    },
     server: {
       port:
         Number(process.env.PORT) ||
@@ -558,6 +755,30 @@ export function loadConfig(): Config {
     },
     appearance: {
       customCSS: fileConfig.appearance?.customCSS || DEFAULT_CONFIG.appearance.customCSS,
+      loginBranding: cleanLoginBranding(
+        {
+          ...(fileConfig.appearance?.loginBranding || {}),
+          productName:
+            process.env.OVERLORD_LOGIN_BRAND_NAME ||
+            fileConfig.appearance?.loginBranding?.productName,
+          title:
+            process.env.OVERLORD_LOGIN_TITLE ||
+            fileConfig.appearance?.loginBranding?.title,
+          subtitle:
+            process.env.OVERLORD_LOGIN_SUBTITLE ||
+            fileConfig.appearance?.loginBranding?.subtitle,
+          iconClass:
+            process.env.OVERLORD_LOGIN_ICON_CLASS ||
+            fileConfig.appearance?.loginBranding?.iconClass,
+          logoUrl:
+            process.env.OVERLORD_LOGIN_LOGO_URL ||
+            fileConfig.appearance?.loginBranding?.logoUrl,
+          logoAlt:
+            process.env.OVERLORD_LOGIN_LOGO_ALT ||
+            fileConfig.appearance?.loginBranding?.logoAlt,
+        },
+        DEFAULT_CONFIG.appearance.loginBranding,
+      ),
     },
     plugins: {
       trustedKeys: (() => {
@@ -828,9 +1049,87 @@ export async function updateTlsConfig(
   return next;
 }
 
-export async function updateAppearanceConfig(customCSS: string): Promise<Config["appearance"]> {
+export async function updateOidcConfig(
+  updates: Partial<Config["oidc"]>,
+): Promise<Config["oidc"]> {
   const current = getConfig();
-  const next = { customCSS: String(customCSS || "").slice(0, 51200) };
+
+  const next: Config["oidc"] = {
+    ...current.oidc,
+    ...updates,
+    enabled:
+      updates.enabled !== undefined
+        ? Boolean(updates.enabled)
+        : current.oidc.enabled,
+    label: String(updates.label ?? current.oidc.label ?? DEFAULT_CONFIG.oidc.label).trim() || DEFAULT_CONFIG.oidc.label,
+    issuer: String(updates.issuer ?? current.oidc.issuer ?? "").trim(),
+    clientId: String(updates.clientId ?? current.oidc.clientId ?? "").trim(),
+    clientSecret:
+      typeof updates.clientSecret === "string" && updates.clientSecret.length > 0
+        ? updates.clientSecret.trim()
+        : current.oidc.clientSecret,
+    redirectUri: String(updates.redirectUri ?? current.oidc.redirectUri ?? "").trim(),
+    scopes: (() => {
+      const scopes = updates.scopes !== undefined ? splitList(updates.scopes) : splitList(current.oidc.scopes);
+      return scopes.length > 0 ? scopes : [...DEFAULT_CONFIG.oidc.scopes];
+    })(),
+    clientAuthMethod: pickClientAuthMethod(updates.clientAuthMethod ?? current.oidc.clientAuthMethod),
+    autoProvision:
+      updates.autoProvision !== undefined
+        ? Boolean(updates.autoProvision)
+        : current.oidc.autoProvision,
+    allowEmailLink:
+      updates.allowEmailLink !== undefined
+        ? Boolean(updates.allowEmailLink)
+        : current.oidc.allowEmailLink,
+    defaultRole: pickRole(updates.defaultRole ?? current.oidc.defaultRole, current.oidc.defaultRole),
+    allowedEmails:
+      updates.allowedEmails !== undefined
+        ? splitList(updates.allowedEmails).map((email) => email.toLowerCase())
+        : splitList(current.oidc.allowedEmails),
+    allowedDomains:
+      updates.allowedDomains !== undefined
+        ? splitList(updates.allowedDomains).map((domain) => domain.toLowerCase())
+        : splitList(current.oidc.allowedDomains),
+    groupClaim: String(updates.groupClaim ?? current.oidc.groupClaim ?? DEFAULT_CONFIG.oidc.groupClaim).trim() || DEFAULT_CONFIG.oidc.groupClaim,
+    adminGroups:
+      updates.adminGroups !== undefined
+        ? splitList(updates.adminGroups)
+        : splitList(current.oidc.adminGroups),
+    operatorGroups:
+      updates.operatorGroups !== undefined
+        ? splitList(updates.operatorGroups)
+        : splitList(current.oidc.operatorGroups),
+    viewerGroups:
+      updates.viewerGroups !== undefined
+        ? splitList(updates.viewerGroups)
+        : splitList(current.oidc.viewerGroups),
+  };
+
+  configCache = {
+    ...current,
+    oidc: next,
+  };
+
+  const fileConfig = readFileConfigForUpdate();
+  fileConfig.oidc = next;
+  await writePersistentFileConfig(fileConfig);
+  return next;
+}
+
+export async function updateAppearanceConfig(
+  customCSS: string,
+  loginBranding?: Partial<Config["appearance"]["loginBranding"]>,
+): Promise<Config["appearance"]> {
+  const current = getConfig();
+  const next: Config["appearance"] = {
+    ...current.appearance,
+    customCSS: String(customCSS || "").slice(0, 51200),
+    loginBranding: cleanLoginBranding(
+      loginBranding ? { ...current.appearance.loginBranding, ...loginBranding } : current.appearance.loginBranding,
+      DEFAULT_CONFIG.appearance.loginBranding,
+    ),
+  };
 
   configCache = {
     ...current,
@@ -1088,6 +1387,10 @@ export function getExportableConfig(serverVersion: string): Record<string, unkno
       jwtSecret: config.auth.jwtSecret,
       agentToken: config.auth.agentToken,
     },
+    oidc: {
+      ...config.oidc,
+      clientSecret: "",
+    },
     notifications: config.notifications,
     security: config.security,
     tls: config.tls,
@@ -1116,6 +1419,8 @@ export async function importFullConfig(data: Record<string, any>): Promise<{ app
     security: process.env.OVERLORD_SESSION_TTL_HOURS || process.env.OVERLORD_LOGIN_MAX_ATTEMPTS,
     tls: process.env.OVERLORD_TLS_CERT || process.env.OVERLORD_TLS_CERTBOT_ENABLED,
     auth: process.env.JWT_SECRET || process.env.OVERLORD_AGENT_TOKEN,
+    oidc: process.env.OVERLORD_OIDC_ENABLED || process.env.OVERLORD_OIDC_ISSUER || process.env.OVERLORD_OIDC_CLIENT_ID,
+    appearance: process.env.OVERLORD_LOGIN_BRAND_NAME || process.env.OVERLORD_LOGIN_LOGO_URL || process.env.OVERLORD_LOGIN_TITLE,
   };
 
   if (data.notifications && typeof data.notifications === "object") {
@@ -1150,8 +1455,15 @@ export async function importFullConfig(data: Record<string, any>): Promise<{ app
   if (data.appearance && typeof data.appearance === "object") {
     const css = typeof data.appearance.customCSS === "string" ? data.appearance.customCSS : "";
     if (css.length <= 51200) {
-      await updateAppearanceConfig(css);
+      const loginBranding =
+        data.appearance.loginBranding && typeof data.appearance.loginBranding === "object"
+          ? data.appearance.loginBranding
+          : undefined;
+      await updateAppearanceConfig(css, loginBranding);
       applied.push("appearance");
+      if (envOverrides.appearance) {
+        warnings.push("Some login branding settings may be overridden by OVERLORD_LOGIN_* environment variables after restart.");
+      }
     } else {
       warnings.push("Custom CSS exceeds 50 KB limit and was skipped.");
     }
@@ -1172,6 +1484,37 @@ export async function importFullConfig(data: Record<string, any>): Promise<{ app
     applied.push("registration");
   }
 
+  if (data.oidc && typeof data.oidc === "object") {
+    const current = getConfig();
+    const next: Config["oidc"] = {
+      ...current.oidc,
+      ...data.oidc,
+      clientSecret:
+        typeof data.oidc.clientSecret === "string" && data.oidc.clientSecret
+          ? data.oidc.clientSecret
+          : current.oidc.clientSecret,
+      enabled: Boolean(data.oidc.enabled),
+      scopes: splitList(data.oidc.scopes).length > 0 ? splitList(data.oidc.scopes) : current.oidc.scopes,
+      clientAuthMethod: pickClientAuthMethod(data.oidc.clientAuthMethod),
+      autoProvision: data.oidc.autoProvision !== undefined ? Boolean(data.oidc.autoProvision) : current.oidc.autoProvision,
+      allowEmailLink: data.oidc.allowEmailLink !== undefined ? Boolean(data.oidc.allowEmailLink) : current.oidc.allowEmailLink,
+      defaultRole: pickRole(data.oidc.defaultRole, current.oidc.defaultRole),
+      allowedEmails: splitList(data.oidc.allowedEmails),
+      allowedDomains: splitList(data.oidc.allowedDomains),
+      adminGroups: splitList(data.oidc.adminGroups),
+      operatorGroups: splitList(data.oidc.operatorGroups),
+      viewerGroups: splitList(data.oidc.viewerGroups),
+    };
+    configCache = { ...current, oidc: next };
+    const fileConfig = readFileConfigForUpdate();
+    fileConfig.oidc = next;
+    await writePersistentFileConfig(fileConfig);
+    applied.push("oidc");
+    if (envOverrides.oidc) {
+      warnings.push("Some OIDC settings may be overridden by OVERLORD_OIDC_* environment variables after restart.");
+    }
+  }
+
   if (data.buildRateLimit && typeof data.buildRateLimit === "object") {
     await updateBuildRateLimitConfig(data.buildRateLimit);
     applied.push("buildRateLimit");
diff --git a/Overlord-Server/src/db/repositories.ts b/Overlord-Server/src/db/repositories.ts
index 2eb8d2d..9e8f5eb 100644
--- a/Overlord-Server/src/db/repositories.ts
+++ b/Overlord-Server/src/db/repositories.ts
@@ -5,6 +5,7 @@ import { db, dbPath } from "./connection";
 import "./schema";
 
 export * from "./repositories/chat";
+export * from "./repositories/oidc";
 export * from "./repositories/revoked-tokens";
 export * from "./repositories/sessions";
 export * from "./repositories/shared-files";
diff --git a/Overlord-Server/src/db/repositories/oidc.ts b/Overlord-Server/src/db/repositories/oidc.ts
new file mode 100644
index 0000000..6796954
--- /dev/null
+++ b/Overlord-Server/src/db/repositories/oidc.ts
@@ -0,0 +1,106 @@
+import { db } from "../connection";
+import "../schema";
+
+export type OidcAuthState = {
+  state: string;
+  nonce: string;
+  codeVerifier: string;
+  returnTo: string | null;
+  createdAt: number;
+  expiresAt: number;
+};
+
+export type OidcIdentityRecord = {
+  issuer: string;
+  subject: string;
+  userId: number;
+  email: string | null;
+  username: string | null;
+  createdAt: number;
+  lastLogin: number;
+};
+
+export function saveOidcAuthState(record: OidcAuthState): void {
+  db.run(
+    `INSERT INTO oidc_auth_states (state, nonce, code_verifier, return_to, created_at, expires_at)
+     VALUES (?, ?, ?, ?, ?, ?)`,
+    record.state,
+    record.nonce,
+    record.codeVerifier,
+    record.returnTo,
+    record.createdAt,
+    record.expiresAt,
+  );
+}
+
+export function takeOidcAuthState(state: string): OidcAuthState | null {
+  const row = db.query<any>(`SELECT * FROM oidc_auth_states WHERE state=?`).get(state);
+  if (!row) return null;
+  db.run(`DELETE FROM oidc_auth_states WHERE state=?`, state);
+  return {
+    state: row.state,
+    nonce: row.nonce,
+    codeVerifier: row.code_verifier,
+    returnTo: row.return_to,
+    createdAt: row.created_at,
+    expiresAt: row.expires_at,
+  };
+}
+
+export function pruneExpiredOidcAuthStates(now = Date.now()): number {
+  const result = db.run(`DELETE FROM oidc_auth_states WHERE expires_at <= ?`, now);
+  return result.changes;
+}
+
+export function getOidcIdentity(issuer: string, subject: string): OidcIdentityRecord | null {
+  const row = db.query<any>(
+    `SELECT * FROM oidc_identities WHERE issuer=? AND subject=?`,
+  ).get(issuer, subject);
+  return row ? mapIdentity(row) : null;
+}
+
+export function getOidcIdentityByEmail(issuer: string, email: string): OidcIdentityRecord | null {
+  const row = db.query<any>(
+    `SELECT * FROM oidc_identities WHERE issuer=? AND LOWER(email)=LOWER(?) LIMIT 1`,
+  ).get(issuer, email);
+  return row ? mapIdentity(row) : null;
+}
+
+export function upsertOidcIdentity(input: {
+  issuer: string;
+  subject: string;
+  userId: number;
+  email?: string | null;
+  username?: string | null;
+  now?: number;
+}): void {
+  const now = input.now ?? Date.now();
+  db.run(
+    `INSERT INTO oidc_identities (issuer, subject, user_id, email, username, created_at, last_login)
+     VALUES (?, ?, ?, ?, ?, ?, ?)
+     ON CONFLICT(issuer, subject) DO UPDATE SET
+       user_id=excluded.user_id,
+       email=excluded.email,
+       username=excluded.username,
+       last_login=excluded.last_login`,
+    input.issuer,
+    input.subject,
+    input.userId,
+    input.email || null,
+    input.username || null,
+    now,
+    now,
+  );
+}
+
+function mapIdentity(row: any): OidcIdentityRecord {
+  return {
+    issuer: row.issuer,
+    subject: row.subject,
+    userId: row.user_id,
+    email: row.email || null,
+    username: row.username || null,
+    createdAt: row.created_at,
+    lastLogin: row.last_login,
+  };
+}
diff --git a/Overlord-Server/src/db/schema.ts b/Overlord-Server/src/db/schema.ts
index f97db2b..cb21348 100644
--- a/Overlord-Server/src/db/schema.ts
+++ b/Overlord-Server/src/db/schema.ts
@@ -302,6 +302,34 @@ db.run(`CREATE INDEX IF NOT EXISTS idx_sessions_user_id ON sessions(user_id);`);
 db.run(`CREATE INDEX IF NOT EXISTS idx_sessions_token_hash ON sessions(token_hash);`);
 db.run(`CREATE INDEX IF NOT EXISTS idx_sessions_expires_at ON sessions(expires_at);`);
 
+db.run(`
+  CREATE TABLE IF NOT EXISTS oidc_auth_states (
+    state TEXT PRIMARY KEY,
+    nonce TEXT NOT NULL,
+    code_verifier TEXT NOT NULL,
+    return_to TEXT,
+    created_at INTEGER NOT NULL,
+    expires_at INTEGER NOT NULL
+  );
+`);
+db.run(`CREATE INDEX IF NOT EXISTS idx_oidc_auth_states_expires_at ON oidc_auth_states(expires_at);`);
+
+db.run(`
+  CREATE TABLE IF NOT EXISTS oidc_identities (
+    issuer TEXT NOT NULL,
+    subject TEXT NOT NULL,
+    user_id INTEGER NOT NULL,
+    email TEXT,
+    username TEXT,
+    created_at INTEGER NOT NULL,
+    last_login INTEGER NOT NULL,
+    PRIMARY KEY (issuer, subject),
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+  );
+`);
+db.run(`CREATE INDEX IF NOT EXISTS idx_oidc_identities_user_id ON oidc_identities(user_id);`);
+db.run(`CREATE INDEX IF NOT EXISTS idx_oidc_identities_email ON oidc_identities(email);`);
+
 db.run(`
   CREATE TABLE IF NOT EXISTS builds (
     id TEXT PRIMARY KEY,
diff --git a/Overlord-Server/src/main-server.ts b/Overlord-Server/src/main-server.ts
index e67176f..58ce1df 100644
--- a/Overlord-Server/src/main-server.ts
+++ b/Overlord-Server/src/main-server.ts
@@ -34,6 +34,7 @@ import { handleClientRoutes } from "./server/routes/client-routes";
 import { handleMiscRoutes } from "./server/routes/misc-routes";
 import { handleKeylogArchiveRoutes } from "./server/routes/keylog-archive-routes";
 import { handleNotificationsConfigRoutes } from "./server/routes/notifications-config-routes";
+import { handleOidcRoutes } from "./server/routes/oidc-routes";
 import { handlePageRoutes } from "./server/routes/page-routes";
 import { handlePluginRoutes } from "./server/routes/plugin-routes";
 import { handleFileShareRoutes } from "./server/routes/file-share-routes";
@@ -712,6 +713,7 @@ async function startServer() {
           requestIP: (srv as any).requestIP,
         }),
         (req, url, srv) => handleAuthRoutes(req, url, srv as any),
+        (req, url, srv) => handleOidcRoutes(req, url, srv as any),
         (req, url, srv) => handleNotificationsConfigRoutes(req, url, srv as any, routeDeps.notificationsConfig),
         (req, url) => handleAutoScriptsRoutes(req, url),
         (req, url) => handleSavedScriptsRoutes(req, url),
diff --git a/Overlord-Server/src/rbac.ts b/Overlord-Server/src/rbac.ts
index 3798e8c..5df370d 100644
--- a/Overlord-Server/src/rbac.ts
+++ b/Overlord-Server/src/rbac.ts
@@ -95,6 +95,10 @@ const PERMISSIONS = {
     description: "Change TLS and certificate settings",
     roles: ["admin"],
   },
+  "system:oidc": {
+    description: "Change OIDC and SSO login settings",
+    roles: ["admin"],
+  },
   "system:registration": {
     description: "Change user registration policy settings",
     roles: ["admin"],
diff --git a/Overlord-Server/src/server/oidc.ts b/Overlord-Server/src/server/oidc.ts
new file mode 100644
index 0000000..4ed3e2c
--- /dev/null
+++ b/Overlord-Server/src/server/oidc.ts
@@ -0,0 +1,489 @@
+import { importJWK, jwtVerify, type JWK, type JWTPayload } from "jose";
+import { getConfig, type Config } from "../config";
+import {
+  getOidcIdentity,
+  getOidcIdentityByEmail,
+  pruneExpiredOidcAuthStates,
+  saveOidcAuthState,
+  takeOidcAuthState,
+  upsertOidcIdentity,
+} from "../db";
+import { logger } from "../logger";
+import {
+  createExternalUser,
+  getUserById,
+  getUserByUsername,
+  updateLastLogin,
+  type User,
+  type UserRole,
+} from "../users";
+import { shouldUseSecureAuthCookie } from "./routes/auth-cookie";
+
+type OidcDiscovery = {
+  issuer: string;
+  authorization_endpoint: string;
+  token_endpoint: string;
+  jwks_uri: string;
+  userinfo_endpoint?: string;
+};
+
+type OidcClaims = JWTPayload & {
+  sub: string;
+  email?: string;
+  email_verified?: boolean;
+  preferred_username?: string;
+  name?: string;
+  groups?: unknown;
+  [key: string]: unknown;
+};
+
+const discoveryCache = new Map<string, { expiresAt: number; metadata: OidcDiscovery }>();
+const jwksCache = new Map<string, { expiresAt: number; keys: JWK[] }>();
+const DISCOVERY_TTL_MS = 60 * 60 * 1000;
+const STATE_TTL_MS = 10 * 60 * 1000;
+const OIDC_STATE_COOKIE = "overlord_oidc_state";
+
+export function getOidcPublicStatus(): { enabled: boolean; label: string; loginUrl: string | null } {
+  const oidc = getConfig().oidc;
+  const configured = Boolean(oidc.enabled && oidc.issuer && oidc.clientId);
+  return {
+    enabled: configured,
+    label: oidc.label || "Single sign-on",
+    loginUrl: configured ? "/api/oidc/login" : null,
+  };
+}
+
+export async function createOidcLoginRedirect(req: Request, url: URL): Promise<Response> {
+  const oidc = getConfig().oidc;
+  if (!isOidcConfigured(oidc)) {
+    return Response.json({ error: "OIDC is not configured" }, { status: 404 });
+  }
+
+  pruneExpiredOidcAuthStates();
+
+  const metadata = await getDiscovery(oidc);
+  const state = randomBase64Url(32);
+  const nonce = randomBase64Url(32);
+  const codeVerifier = randomBase64Url(48);
+  const codeChallenge = await pkceChallenge(codeVerifier);
+  const redirectUri = getRedirectUri(oidc, url);
+  const returnTo = normalizeReturnTo(url.searchParams.get("returnTo") || req.headers.get("Referer"));
+  const now = Date.now();
+
+  saveOidcAuthState({
+    state,
+    nonce,
+    codeVerifier,
+    returnTo,
+    createdAt: now,
+    expiresAt: now + STATE_TTL_MS,
+  });
+
+  const authUrl = new URL(metadata.authorization_endpoint);
+  authUrl.searchParams.set("response_type", "code");
+  authUrl.searchParams.set("client_id", oidc.clientId);
+  authUrl.searchParams.set("redirect_uri", redirectUri);
+  authUrl.searchParams.set("scope", normalizeScopes(oidc.scopes).join(" "));
+  authUrl.searchParams.set("state", state);
+  authUrl.searchParams.set("nonce", nonce);
+  authUrl.searchParams.set("code_challenge", codeChallenge);
+  authUrl.searchParams.set("code_challenge_method", "S256");
+
+  const headers = new Headers({ Location: authUrl.toString() });
+  headers.append("Set-Cookie", makeOidcStateCookie(state, req));
+  return new Response(null, { status: 302, headers });
+}
+
+export async function completeOidcLogin(req: Request, url: URL): Promise<{ user: User; returnTo: string }> {
+  const oidc = getConfig().oidc;
+  if (!isOidcConfigured(oidc)) {
+    throw new Error("OIDC is not configured");
+  }
+
+  const error = url.searchParams.get("error");
+  if (error) {
+    const description = url.searchParams.get("error_description");
+    throw new Error(description || error);
+  }
+
+  const code = url.searchParams.get("code") || "";
+  const state = url.searchParams.get("state") || "";
+  if (!code || !state) {
+    throw new Error("Missing OIDC callback parameters");
+  }
+
+  if (getOidcStateCookie(req) !== state) {
+    throw new Error("OIDC state cookie mismatch. Please try again.");
+  }
+
+  const savedState = takeOidcAuthState(state);
+  if (!savedState || savedState.expiresAt <= Date.now()) {
+    throw new Error("OIDC login expired. Please try again.");
+  }
+
+  const metadata = await getDiscovery(oidc);
+  const redirectUri = getRedirectUri(oidc, url);
+  const tokenSet = await exchangeCodeForTokens(oidc, metadata, {
+    code,
+    codeVerifier: savedState.codeVerifier,
+    redirectUri,
+  });
+
+  const idToken = typeof tokenSet.id_token === "string" ? tokenSet.id_token : "";
+  if (!idToken) {
+    throw new Error("OIDC provider did not return an ID token");
+  }
+
+  const claims = await verifyIdToken(oidc, metadata, idToken, savedState.nonce);
+  const mergedClaims = await maybeFetchUserinfo(metadata, tokenSet.access_token, claims);
+  const user = await resolveOidcUser(oidc, metadata.issuer, mergedClaims);
+
+  return { user, returnTo: savedState.returnTo || "/" };
+}
+
+function isOidcConfigured(oidc: Config["oidc"]): boolean {
+  return Boolean(oidc.enabled && oidc.issuer && oidc.clientId);
+}
+
+async function getDiscovery(oidc: Config["oidc"]): Promise<OidcDiscovery> {
+  const issuer = normalizeIssuerUrl(oidc.issuer);
+  const cached = discoveryCache.get(issuer);
+  if (cached && cached.expiresAt > Date.now()) return cached.metadata;
+
+  const res = await fetch(`${issuer}/.well-known/openid-configuration`, {
+    headers: { Accept: "application/json" },
+  });
+  if (!res.ok) throw new Error(`OIDC discovery failed (${res.status})`);
+
+  const metadata = await res.json() as OidcDiscovery;
+  if (!metadata.authorization_endpoint || !metadata.token_endpoint || !metadata.jwks_uri) {
+    throw new Error("OIDC discovery document is missing required endpoints");
+  }
+
+  const discoveredIssuer = normalizeIssuerUrl(metadata.issuer || "");
+  if (discoveredIssuer !== issuer) {
+    throw new Error("OIDC discovery issuer does not match the configured issuer");
+  }
+
+  const normalized = {
+    ...metadata,
+    issuer: discoveredIssuer,
+    authorization_endpoint: requireHttpsUrl(metadata.authorization_endpoint, "authorization_endpoint"),
+    token_endpoint: requireHttpsUrl(metadata.token_endpoint, "token_endpoint"),
+    jwks_uri: requireHttpsUrl(metadata.jwks_uri, "jwks_uri"),
+    userinfo_endpoint: metadata.userinfo_endpoint
+      ? requireHttpsUrl(metadata.userinfo_endpoint, "userinfo_endpoint")
+      : undefined,
+  };
+  discoveryCache.set(issuer, {
+    expiresAt: Date.now() + DISCOVERY_TTL_MS,
+    metadata: normalized,
+  });
+  return normalized;
+}
+
+async function exchangeCodeForTokens(
+  oidc: Config["oidc"],
+  metadata: OidcDiscovery,
+  input: { code: string; codeVerifier: string; redirectUri: string },
+): Promise<Record<string, any>> {
+  const body = new URLSearchParams({
+    grant_type: "authorization_code",
+    code: input.code,
+    redirect_uri: input.redirectUri,
+    client_id: oidc.clientId,
+    code_verifier: input.codeVerifier,
+  });
+
+  const headers: Record<string, string> = {
+    Accept: "application/json",
+    "Content-Type": "application/x-www-form-urlencoded",
+  };
+
+  if (oidc.clientAuthMethod === "client_secret_post" && oidc.clientSecret) {
+    body.set("client_secret", oidc.clientSecret);
+  } else if (oidc.clientAuthMethod === "client_secret_basic" && oidc.clientSecret) {
+    headers.Authorization = `Basic ${Buffer.from(`${oidc.clientId}:${oidc.clientSecret}`).toString("base64")}`;
+  }
+
+  const res = await fetch(metadata.token_endpoint, {
+    method: "POST",
+    headers,
+    body,
+  });
+  const payload = await res.json().catch(() => ({}));
+  if (!res.ok) {
+    const detail = typeof payload.error_description === "string"
+      ? payload.error_description
+      : typeof payload.error === "string"
+        ? payload.error
+        : `HTTP ${res.status}`;
+    throw new Error(`OIDC token exchange failed: ${detail}`);
+  }
+  return payload;
+}
+
+async function verifyIdToken(
+  oidc: Config["oidc"],
+  metadata: OidcDiscovery,
+  idToken: string,
+  nonce: string,
+): Promise<OidcClaims> {
+  const { payload } = await jwtVerify(idToken, async (protectedHeader) => {
+    const key = await getJwkForHeader(metadata, protectedHeader.kid, protectedHeader.alg);
+    return importJWK(key, protectedHeader.alg);
+  }, {
+    issuer: metadata.issuer,
+    audience: oidc.clientId,
+  });
+  if (payload.nonce !== nonce) {
+    throw new Error("OIDC nonce mismatch");
+  }
+  if (typeof payload.sub !== "string" || !payload.sub) {
+    throw new Error("OIDC ID token is missing subject");
+  }
+  return payload as OidcClaims;
+}
+
+async function getJwkForHeader(metadata: OidcDiscovery, kid?: string, alg?: string): Promise<JWK> {
+  const keys = await getJwks(metadata.jwks_uri);
+  const key = keys.find((candidate) =>
+    (!kid || candidate.kid === kid) &&
+    (!alg || !candidate.alg || candidate.alg === alg) &&
+    (!candidate.use || candidate.use === "sig"),
+  );
+  if (!key) {
+    throw new Error("OIDC signing key was not found in JWKS");
+  }
+  return key;
+}
+
+async function getJwks(jwksUri: string): Promise<JWK[]> {
+  const cached = jwksCache.get(jwksUri);
+  if (cached && cached.expiresAt > Date.now()) return cached.keys;
+
+  const res = await fetch(jwksUri, { headers: { Accept: "application/json" } });
+  if (!res.ok) throw new Error(`OIDC JWKS request failed (${res.status})`);
+  const body = await res.json() as { keys?: JWK[] };
+  const keys = Array.isArray(body.keys) ? body.keys : [];
+  if (!keys.length) throw new Error("OIDC JWKS did not contain signing keys");
+  jwksCache.set(jwksUri, { expiresAt: Date.now() + 10 * 60 * 1000, keys });
+  return keys;
+}
+
+async function maybeFetchUserinfo(
+  metadata: OidcDiscovery,
+  accessToken: unknown,
+  claims: OidcClaims,
+): Promise<OidcClaims> {
+  if (!metadata.userinfo_endpoint || typeof accessToken !== "string" || !accessToken) {
+    return claims;
+  }
+  try {
+    const res = await fetch(metadata.userinfo_endpoint, {
+      headers: { Accept: "application/json", Authorization: `Bearer ${accessToken}` },
+    });
+    if (!res.ok) return claims;
+    const userinfo = await res.json();
+    return { ...claims, ...userinfo, sub: claims.sub };
+  } catch (err) {
+    logger.warn("[oidc] userinfo request failed", err);
+    return claims;
+  }
+}
+
+export async function resolveOidcUser(oidc: Config["oidc"], issuer: string, claims: OidcClaims): Promise<User> {
+  const email = typeof claims.email === "string" ? claims.email.trim().toLowerCase() : "";
+  const usernameClaim = typeof claims.preferred_username === "string"
+    ? claims.preferred_username
+    : typeof claims.name === "string"
+      ? claims.name
+      : "";
+
+  enforceAllowedIdentity(oidc, email);
+
+  const existingIdentity = getOidcIdentity(issuer, claims.sub);
+  if (existingIdentity) {
+    const existingUser = getUserById(existingIdentity.userId);
+    if (existingUser) {
+      updateLastLogin(existingUser.id);
+      upsertOidcIdentity({
+        issuer,
+        subject: claims.sub,
+        userId: existingUser.id,
+        email,
+        username: usernameClaim,
+      });
+      return existingUser;
+    }
+  }
+
+  if (oidc.allowEmailLink && email && claims.email_verified === true) {
+    const existingEmailIdentity = getOidcIdentityByEmail(issuer, email);
+    if (existingEmailIdentity) {
+      const user = getUserById(existingEmailIdentity.userId);
+      if (user) {
+        updateLastLogin(user.id);
+        upsertOidcIdentity({ issuer, subject: claims.sub, userId: user.id, email, username: usernameClaim });
+        return user;
+      }
+    }
+  }
+
+  if (!oidc.autoProvision) {
+    throw new Error("No linked Overlord account exists for this OIDC identity");
+  }
+
+  const username = pickAvailableUsername(usernameClaim || email.split("@")[0] || `oidc_${claims.sub.slice(0, 12)}`);
+  const role = roleFromClaims(oidc, claims);
+  const created = await createExternalUser(username, role, "oidc", "oidc");
+  if (!created.success || !created.userId) {
+    throw new Error(created.error || "Failed to provision OIDC user");
+  }
+
+  upsertOidcIdentity({ issuer, subject: claims.sub, userId: created.userId, email, username: usernameClaim });
+  updateLastLogin(created.userId);
+  const user = getUserById(created.userId);
+  if (!user) throw new Error("Provisioned user could not be loaded");
+  return user;
+}
+
+function enforceAllowedIdentity(oidc: Config["oidc"], email: string): void {
+  const allowedEmails = oidc.allowedEmails.map((v) => v.toLowerCase());
+  const allowedDomains = oidc.allowedDomains.map((v) => v.toLowerCase().replace(/^@/, ""));
+
+  if (allowedEmails.length > 0 && (!email || !allowedEmails.includes(email))) {
+    throw new Error("This OIDC account is not allowed to access Overlord");
+  }
+
+  if (allowedDomains.length > 0) {
+    const domain = email.includes("@") ? email.split("@").pop()!.toLowerCase() : "";
+    if (!domain || !allowedDomains.includes(domain)) {
+      throw new Error("This OIDC email domain is not allowed to access Overlord");
+    }
+  }
+}
+
+function roleFromClaims(oidc: Config["oidc"], claims: OidcClaims): UserRole {
+  const groups = getClaimStrings(claims[oidc.groupClaim || "groups"]);
+  const hasGroup = (configured: string[]) => configured.some((group) => groups.has(group));
+  if (hasGroup(oidc.adminGroups)) return "admin";
+  if (hasGroup(oidc.operatorGroups)) return "operator";
+  if (hasGroup(oidc.viewerGroups)) return "viewer";
+  return oidc.defaultRole;
+}
+
+function getClaimStrings(value: unknown): Set<string> {
+  if (Array.isArray(value)) return new Set(value.map((v) => String(v)));
+  if (typeof value === "string" && value.trim()) return new Set([value.trim()]);
+  return new Set();
+}
+
+function pickAvailableUsername(seed: string): string {
+  const base = sanitizeUsername(seed) || "oidc_user";
+  if (!getUserByUsername(base)) return base;
+  const trimmed = base.slice(0, 27);
+  for (let i = 1; i < 1000; i++) {
+    const candidate = `${trimmed}_${i}`;
+    if (!getUserByUsername(candidate)) return candidate;
+  }
+  return `oidc_${randomBase64Url(8)}`.slice(0, 32);
+}
+
+function sanitizeUsername(value: string): string {
+  const cleaned = value
+    .toLowerCase()
+    .replace(/[^a-z0-9_-]+/g, "_")
+    .replace(/^_+|_+$/g, "")
+    .slice(0, 32);
+  return cleaned.length >= 3 ? cleaned : "";
+}
+
+function normalizeScopes(scopes: string[]): string[] {
+  const result = Array.from(new Set(["openid", ...scopes.map((s) => String(s).trim()).filter(Boolean)]));
+  return result;
+}
+
+function getRedirectUri(oidc: Config["oidc"], url: URL): string {
+  return oidc.redirectUri || new URL("/api/oidc/callback", url.origin).toString();
+}
+
+export function makeOidcStateCookie(state: string, req: Request): string {
+  const securePart = shouldUseSecureAuthCookie(req) ? "Secure; " : "";
+  return `${OIDC_STATE_COOKIE}=${state}; HttpOnly; ${securePart}SameSite=Lax; Path=/api/oidc/callback; Max-Age=${Math.ceil(STATE_TTL_MS / 1000)}`;
+}
+
+export function makeOidcStateCookieClear(req: Request): string {
+  const securePart = shouldUseSecureAuthCookie(req) ? "Secure; " : "";
+  return `${OIDC_STATE_COOKIE}=; HttpOnly; ${securePart}SameSite=Lax; Path=/api/oidc/callback; Max-Age=0`;
+}
+
+function getOidcStateCookie(req: Request): string | null {
+  const cookieHeader = req.headers.get("Cookie");
+  if (!cookieHeader) return null;
+
+  const cookies = cookieHeader.split(/;\s*/);
+  for (const cookie of cookies) {
+    const [name, ...valueParts] = cookie.split("=");
+    if (name === OIDC_STATE_COOKIE) {
+      return valueParts.join("=") || null;
+    }
+  }
+  return null;
+}
+
+function normalizeIssuerUrl(value: string): string {
+  let parsed: URL;
+  try {
+    parsed = new URL(value);
+  } catch {
+    throw new Error("OIDC issuer must be a valid HTTPS URL");
+  }
+  if (parsed.protocol !== "https:") {
+    throw new Error("OIDC issuer must use HTTPS");
+  }
+  if (parsed.username || parsed.password) {
+    throw new Error("OIDC issuer must not include credentials");
+  }
+  return parsed.toString().replace(/\/+$/, "");
+}
+
+function requireHttpsUrl(value: string, field: string): string {
+  let parsed: URL;
+  try {
+    parsed = new URL(value);
+  } catch {
+    throw new Error(`OIDC ${field} must be a valid HTTPS URL`);
+  }
+  if (parsed.protocol !== "https:") {
+    throw new Error(`OIDC ${field} must use HTTPS`);
+  }
+  if (parsed.username || parsed.password) {
+    throw new Error(`OIDC ${field} must not include credentials`);
+  }
+  return parsed.toString();
+}
+
+function normalizeReturnTo(value: string | null): string | null {
+  if (!value) return null;
+  try {
+    const url = new URL(value, "https://placeholder.local");
+    const relative = `${url.pathname}${url.search}${url.hash}`;
+    if (!relative.startsWith("/") || relative.startsWith("//")) return null;
+    if (relative.startsWith("/api/")) return null;
+    return relative;
+  } catch {
+    return null;
+  }
+}
+
+function randomBase64Url(bytes: number): string {
+  const buf = new Uint8Array(bytes);
+  crypto.getRandomValues(buf);
+  return Buffer.from(buf).toString("base64url");
+}
+
+async function pkceChallenge(verifier: string): Promise<string> {
+  const digest = await crypto.subtle.digest("SHA-256", new TextEncoder().encode(verifier));
+  return Buffer.from(digest).toString("base64url");
+}
diff --git a/Overlord-Server/src/server/routes/auth-routes.ts b/Overlord-Server/src/server/routes/auth-routes.ts
index 0949792..a19d64a 100644
--- a/Overlord-Server/src/server/routes/auth-routes.ts
+++ b/Overlord-Server/src/server/routes/auth-routes.ts
@@ -8,6 +8,7 @@ import {
   revokeToken,
 } from "../../auth";
 import { AuditAction, logAudit } from "../../auditLog";
+import { getConfig } from "../../config";
 import { buildTotpUri, generateMfaSecret, verifyTotpCode } from "../../mfa";
 import { createQrSvg } from "../../qr";
 import {
@@ -50,6 +51,10 @@ export async function handleAuthRoutes(
   url: URL,
   server: RequestIpProvider,
 ): Promise<Response | null> {
+  if (req.method === "GET" && url.pathname === "/api/login/branding") {
+    return Response.json(getConfig().appearance.loginBranding);
+  }
+
   if (req.method === "POST" && url.pathname === "/api/login") {
     const ip = server.requestIP(req)?.address || "unknown";
 
diff --git a/Overlord-Server/src/server/routes/misc-routes.ts b/Overlord-Server/src/server/routes/misc-routes.ts
index ea75ff6..480a36b 100644
--- a/Overlord-Server/src/server/routes/misc-routes.ts
+++ b/Overlord-Server/src/server/routes/misc-routes.ts
@@ -1,7 +1,7 @@
 import { authenticateRequest } from "../../auth";
 import { AuditAction, getAuditLogs, logAudit } from "../../auditLog";
 import { logger } from "../../logger";
-import { getConfig, updateSecurityConfig, updateTlsConfig, updateAppearanceConfig, updateChatConfig, getExportableConfig, importFullConfig, updateRegistrationConfig, updateBuildRateLimitConfig, updateThumbnailsConfig, updateInputArchiveConfig } from "../../config";
+import { getConfig, updateSecurityConfig, updateTlsConfig, updateOidcConfig, updateAppearanceConfig, updateChatConfig, getExportableConfig, importFullConfig, updateRegistrationConfig, updateBuildRateLimitConfig, updateThumbnailsConfig, updateInputArchiveConfig } from "../../config";
 import {
   getClientMetricsSummary,
   getClientMetricsSummaryForUser,
@@ -39,6 +39,15 @@ type MiscRouteDeps = {
   tlsSource?: "certbot" | "configured" | "self-signed";
 };
 
+function maskOidcSettings() {
+  const oidc = getConfig().oidc;
+  return {
+    ...oidc,
+    clientSecret: "",
+    clientSecretSet: Boolean(oidc.clientSecret),
+  };
+}
+
 function clampProfileDuration(value: unknown): number {
   const parsed = Number(value);
   if (!Number.isFinite(parsed)) return 5000;
@@ -686,6 +695,63 @@ export async function handleMiscRoutes(
     }
   }
 
+  if (url.pathname === "/api/settings/oidc") {
+    const user = await authenticateRequest(req);
+    if (!user) {
+      return new Response("Unauthorized", { status: 401 });
+    }
+    try {
+      requirePermission(user, "system:oidc");
+    } catch (error) {
+      if (error instanceof Response) return error;
+      return new Response("Forbidden", { status: 403 });
+    }
+
+    if (req.method === "GET") {
+      return Response.json({ oidc: maskOidcSettings() }, { headers: deps.CORS_HEADERS });
+    }
+
+    if (req.method === "PUT") {
+      let body: any = {};
+      try {
+        body = await req.json();
+      } catch {
+        return Response.json({ error: "Invalid JSON" }, { status: 400 });
+      }
+
+      const updated = await updateOidcConfig({
+        enabled: Boolean(body?.enabled),
+        label: typeof body?.label === "string" ? body.label : undefined,
+        issuer: typeof body?.issuer === "string" ? body.issuer : undefined,
+        clientId: typeof body?.clientId === "string" ? body.clientId : undefined,
+        clientSecret: typeof body?.clientSecret === "string" && body.clientSecret.length > 0 ? body.clientSecret : undefined,
+        redirectUri: typeof body?.redirectUri === "string" ? body.redirectUri : undefined,
+        scopes: body?.scopes,
+        clientAuthMethod: body?.clientAuthMethod,
+        autoProvision: Boolean(body?.autoProvision),
+        allowEmailLink: Boolean(body?.allowEmailLink),
+        defaultRole: body?.defaultRole,
+        allowedEmails: body?.allowedEmails,
+        allowedDomains: body?.allowedDomains,
+        groupClaim: typeof body?.groupClaim === "string" ? body.groupClaim : undefined,
+        adminGroups: body?.adminGroups,
+        operatorGroups: body?.operatorGroups,
+        viewerGroups: body?.viewerGroups,
+      });
+
+      logAudit({
+        timestamp: Date.now(),
+        username: user.username,
+        ip: deps.requestIP?.(req)?.address || "unknown",
+        action: AuditAction.COMMAND,
+        details: `Updated OIDC settings (enabled=${updated.enabled})`,
+        success: true,
+      });
+
+      return Response.json({ ok: true, oidc: maskOidcSettings() }, { headers: deps.CORS_HEADERS });
+    }
+  }
+
   if (req.method === "POST" && url.pathname === "/api/settings/tls/certbot/setup") {
     const user = await authenticateRequest(req);
     if (!user) {
@@ -1135,8 +1201,12 @@ export async function handleMiscRoutes(
     }
 
     if (req.method === "GET") {
+      const appearance = getConfig().appearance;
       return Response.json(
-        { customCSS: getConfig().appearance?.customCSS || "" },
+        {
+          customCSS: appearance?.customCSS || "",
+          loginBranding: appearance.loginBranding,
+        },
         { headers: deps.CORS_HEADERS },
       );
     }
@@ -1153,8 +1223,12 @@ export async function handleMiscRoutes(
       if (customCSS.length > 51200) {
         return Response.json({ error: "CSS exceeds 50 KB limit" }, { status: 400 });
       }
+      const loginBranding =
+        body?.loginBranding && typeof body.loginBranding === "object"
+          ? body.loginBranding
+          : undefined;
 
-      const updated = await updateAppearanceConfig(customCSS);
+      const updated = await updateAppearanceConfig(customCSS, loginBranding);
 
       logAudit({
         timestamp: Date.now(),
@@ -1165,7 +1239,10 @@ export async function handleMiscRoutes(
         success: true,
       });
 
-      return Response.json({ ok: true, customCSS: updated.customCSS }, { headers: deps.CORS_HEADERS });
+      return Response.json(
+        { ok: true, customCSS: updated.customCSS, loginBranding: updated.loginBranding },
+        { headers: deps.CORS_HEADERS },
+      );
     }
   }
 
diff --git a/Overlord-Server/src/server/routes/oidc-routes.test.ts b/Overlord-Server/src/server/routes/oidc-routes.test.ts
new file mode 100644
index 0000000..29067e8
--- /dev/null
+++ b/Overlord-Server/src/server/routes/oidc-routes.test.ts
@@ -0,0 +1,177 @@
+import { afterAll, beforeAll, describe, expect, test } from "bun:test";
+import { getConfig, updateOidcConfig, updateSecurityConfig, type Config } from "../../config";
+import { createUser } from "../../users";
+import { createOidcLoginRedirect, resolveOidcUser } from "../oidc";
+import { getOidcLocalMfaBlockReason, handleOidcRoutes } from "./oidc-routes";
+
+const server = {
+  requestIP: () => ({ address: "127.0.0.1" }),
+};
+
+let originalOidc: Config["oidc"];
+let originalSecurity: Config["security"];
+const originalFetch = globalThis.fetch;
+
+beforeAll(() => {
+  originalOidc = { ...getConfig().oidc, scopes: [...getConfig().oidc.scopes] };
+  originalSecurity = { ...getConfig().security };
+});
+
+afterAll(async () => {
+  globalThis.fetch = originalFetch;
+  await updateOidcConfig(originalOidc);
+  await updateSecurityConfig(originalSecurity);
+});
+
+describe("OIDC routes", () => {
+  test("status reports disabled when OIDC is not configured", async () => {
+    const req = new Request("https://localhost/api/oidc/status");
+    const url = new URL(req.url);
+
+    const res = await handleOidcRoutes(req, url, server);
+
+    expect(res?.status).toBe(200);
+    const body = await res!.json();
+    expect(body.enabled).toBe(false);
+    expect(body.loginUrl).toBeNull();
+  });
+
+  test("login redirect stores a browser-bound OIDC state cookie", async () => {
+    const issuer = `https://oidc-state-${Date.now()}.example.test`;
+    await configureOidc(issuer);
+    mockDiscovery(issuer);
+
+    const req = new Request("https://localhost/api/oidc/login?returnTo=/settings.html");
+    const res = await createOidcLoginRedirect(req, new URL(req.url));
+
+    expect(res.status).toBe(302);
+    expect(res.headers.get("Set-Cookie")).toContain("overlord_oidc_state=");
+    expect(res.headers.get("Set-Cookie")).toContain("HttpOnly");
+    expect(res.headers.get("Set-Cookie")).toContain("SameSite=Lax");
+
+    const redirect = new URL(res.headers.get("Location")!);
+    expect(redirect.searchParams.get("state")).toBeTruthy();
+    expect(redirect.searchParams.get("code_challenge_method")).toBe("S256");
+  });
+
+  test("callback rejects state values that are not bound to the browser cookie", async () => {
+    const issuer = `https://oidc-csrf-${Date.now()}.example.test`;
+    await configureOidc(issuer);
+    mockDiscovery(issuer);
+
+    const loginReq = new Request("https://localhost/api/oidc/login");
+    const loginRes = await createOidcLoginRedirect(loginReq, new URL(loginReq.url));
+    const state = new URL(loginRes.headers.get("Location")!).searchParams.get("state")!;
+
+    const callbackReq = new Request(`https://localhost/api/oidc/callback?code=fake-code&state=${state}`);
+    const callbackRes = await handleOidcRoutes(callbackReq, new URL(callbackReq.url), server);
+
+    expect(callbackRes?.status).toBe(302);
+    const location = new URL(callbackRes!.headers.get("Location")!);
+    expect(location.pathname).toBe("/login.html");
+    expect(location.searchParams.get("oidc_error")).toContain("state cookie mismatch");
+    expect(callbackRes!.headers.get("Set-Cookie")).toContain("overlord_oidc_state=;");
+  });
+
+  test("login redirect rejects non-HTTPS issuers before discovery", async () => {
+    await configureOidc("http://oidc-insecure.example.test");
+    setMockFetch(async () => {
+      throw new Error("fetch should not be called for insecure issuer");
+    });
+
+    const req = new Request("https://localhost/api/oidc/login");
+    await expect(createOidcLoginRedirect(req, new URL(req.url))).rejects.toThrow("HTTPS");
+  });
+
+  test("email linking does not fall back to local usernames", async () => {
+    const username = `oidc_link_${Date.now().toString(36)}`;
+    const created = await createUser(username, "Aa1!VeryLongTestPassword_2026", "operator", "test");
+    expect(created.success).toBe(true);
+
+    const oidc: Config["oidc"] = {
+      ...getConfig().oidc,
+      enabled: true,
+      issuer: "https://issuer.example.test",
+      clientId: "client",
+      allowEmailLink: true,
+      autoProvision: false,
+      allowedEmails: [],
+      allowedDomains: [],
+    };
+
+    await expect(resolveOidcUser(oidc, "https://issuer.example.test", {
+      sub: `subject-${Date.now()}`,
+      email: `${username}@example.test`,
+      email_verified: true,
+      preferred_username: "not-local",
+    } as any)).rejects.toThrow("No linked Overlord account exists");
+  });
+
+  test("OIDC session issuance is blocked when local MFA is enabled or required", async () => {
+    await updateSecurityConfig({
+      ...getConfig().security,
+      mfaRequiredForAdmins: true,
+      mfaRequiredForNonAdmins: false,
+    });
+
+    expect(getOidcLocalMfaBlockReason({
+      role: "operator",
+      mfa_enabled: 1,
+      mfa_secret: "secret",
+    })).toContain("Local MFA is enabled");
+
+    expect(getOidcLocalMfaBlockReason({
+      role: "admin",
+      mfa_enabled: 0,
+      mfa_secret: null,
+    })).toContain("Local MFA is required");
+
+    expect(getOidcLocalMfaBlockReason({
+      role: "operator",
+      mfa_enabled: 0,
+      mfa_secret: null,
+    })).toBeNull();
+  });
+});
+
+async function configureOidc(issuer: string): Promise<void> {
+  await updateOidcConfig({
+    enabled: true,
+    issuer,
+    clientId: "overlord-test",
+    clientSecret: "secret",
+    redirectUri: "https://localhost/api/oidc/callback",
+    scopes: ["openid", "profile", "email"],
+    clientAuthMethod: "client_secret_post",
+    autoProvision: false,
+    allowEmailLink: false,
+    defaultRole: "viewer",
+    allowedEmails: [],
+    allowedDomains: [],
+    groupClaim: "groups",
+    adminGroups: [],
+    operatorGroups: [],
+    viewerGroups: [],
+  });
+}
+
+function mockDiscovery(issuer: string): void {
+  setMockFetch(async (input: RequestInfo | URL) => {
+    const url = String(input);
+    if (url === `${issuer}/.well-known/openid-configuration`) {
+      return Response.json({
+        issuer,
+        authorization_endpoint: `${issuer}/authorize`,
+        token_endpoint: `${issuer}/token`,
+        jwks_uri: `${issuer}/jwks`,
+      });
+    }
+    throw new Error(`Unexpected OIDC fetch: ${url}`);
+  });
+}
+
+function setMockFetch(handler: (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>): void {
+  globalThis.fetch = Object.assign(handler, {
+    preconnect: originalFetch.preconnect,
+  }) as typeof fetch;
+}
diff --git a/Overlord-Server/src/server/routes/oidc-routes.ts b/Overlord-Server/src/server/routes/oidc-routes.ts
new file mode 100644
index 0000000..98202a9
--- /dev/null
+++ b/Overlord-Server/src/server/routes/oidc-routes.ts
@@ -0,0 +1,98 @@
+import { generateToken, getSessionTtlSeconds } from "../../auth";
+import { AuditAction, logAudit } from "../../auditLog";
+import { logger } from "../../logger";
+import { isMfaRequiredForUser, type User } from "../../users";
+import {
+  completeOidcLogin,
+  createOidcLoginRedirect,
+  getOidcPublicStatus,
+  makeOidcStateCookieClear,
+} from "../oidc";
+import { makeAuthCookie } from "./auth-cookie";
+
+type RequestIpProvider = {
+  requestIP: (req: Request) => { address?: string } | null | undefined;
+};
+
+export async function handleOidcRoutes(
+  req: Request,
+  url: URL,
+  server: RequestIpProvider,
+): Promise<Response | null> {
+  if (req.method === "GET" && url.pathname === "/api/oidc/status") {
+    return Response.json(getOidcPublicStatus());
+  }
+
+  if (req.method === "GET" && url.pathname === "/api/oidc/login") {
+    try {
+      return await createOidcLoginRedirect(req, url);
+    } catch (error) {
+      logger.error("[oidc] login redirect failed", error);
+      return redirectToLoginError(url, "OIDC login is not available");
+    }
+  }
+
+  if (req.method === "GET" && url.pathname === "/api/oidc/callback") {
+    const ip = server.requestIP(req)?.address || "unknown";
+    try {
+      const { user, returnTo } = await completeOidcLogin(req, url);
+      const mfaBlockReason = getOidcLocalMfaBlockReason(user);
+      if (mfaBlockReason) throw new Error(mfaBlockReason);
+
+      const userAgent = req.headers.get("User-Agent") || null;
+      const token = await generateToken(user, { ip, userAgent: userAgent || undefined });
+      const headers = new Headers({
+        "Location": new URL(returnTo, url.origin).toString(),
+      });
+      headers.append("Set-Cookie", makeAuthCookie(token, getSessionTtlSeconds(), req));
+      headers.append("Set-Cookie", makeOidcStateCookieClear(req));
+
+      logAudit({
+        timestamp: Date.now(),
+        username: user.username,
+        ip,
+        action: AuditAction.LOGIN,
+        success: true,
+        details: "OIDC login",
+      });
+
+      return new Response(null, {
+        status: 302,
+        headers,
+      });
+    } catch (error) {
+      logger.warn("[oidc] callback failed", error);
+      logAudit({
+        timestamp: Date.now(),
+        username: "unknown",
+        ip,
+        action: AuditAction.LOGIN_FAILED,
+        success: false,
+        errorMessage: error instanceof Error ? error.message : String(error),
+      });
+      return redirectToLoginError(url, error instanceof Error ? error.message : "OIDC login failed", req);
+    }
+  }
+
+  return null;
+}
+
+export function getOidcLocalMfaBlockReason(
+  user: Pick<User, "role" | "mfa_enabled" | "mfa_secret">,
+): string | null {
+  if (user.mfa_enabled && user.mfa_secret) {
+    return "Local MFA is enabled for this account. Use password login to complete MFA.";
+  }
+  if (isMfaRequiredForUser(user)) {
+    return "Local MFA is required for this account and cannot be completed through OIDC.";
+  }
+  return null;
+}
+
+function redirectToLoginError(url: URL, message: string, req?: Request): Response {
+  const loginUrl = new URL("/login.html", url.origin);
+  loginUrl.searchParams.set("oidc_error", message);
+  const headers = new Headers({ Location: loginUrl.toString() });
+  if (req) headers.append("Set-Cookie", makeOidcStateCookieClear(req));
+  return new Response(null, { status: 302, headers });
+}
diff --git a/Overlord-Server/src/users.ts b/Overlord-Server/src/users.ts
index 54f0084..4eb9ca4 100644
--- a/Overlord-Server/src/users.ts
+++ b/Overlord-Server/src/users.ts
@@ -713,6 +713,63 @@ export async function createUser(
   }
 }
 
+export async function createExternalUser(
+  username: string,
+  role: UserRole,
+  createdBy: string,
+  registeredVia: string,
+): Promise<{ success: boolean; error?: string; userId?: number }> {
+  if (!username || username.length < 3 || username.length > 32) {
+    return {
+      success: false,
+      error: "Username must be between 3 and 32 characters",
+    };
+  }
+
+  if (!/^[a-zA-Z0-9_-]+$/.test(username)) {
+    return {
+      success: false,
+      error: "Username can only contain letters, numbers, hyphens, and underscores",
+    };
+  }
+
+  const existing = getUserByUsername(username);
+  if (existing) {
+    return { success: false, error: "Username already exists" };
+  }
+
+  try {
+    const passwordHash = await Bun.password.hash(crypto.randomUUID() + crypto.randomUUID(), {
+      algorithm: "bcrypt",
+      cost: 10,
+    });
+
+    const result = db
+      .prepare(
+        "INSERT INTO users (username, password_hash, role, created_at, created_by, must_change_password, client_scope, plugin_scope, can_build, can_upload_files, registered_via) VALUES (?, ?, ?, ?, ?, 0, ?, ?, ?, ?, ?)",
+      )
+      .run(
+        username,
+        passwordHash,
+        role,
+        Date.now(),
+        createdBy,
+        role === "admin" ? "all" : "none",
+        role === "admin" ? "all" : "none",
+        role === "admin" || role === "operator" ? 1 : 0,
+        role === "admin" ? 1 : 0,
+        registeredVia,
+      );
+
+    invalidateNotificationDeliveryCache();
+
+    return { success: true, userId: result.lastInsertRowid as number };
+  } catch (err: any) {
+    logger.error("[users] Create external user error:", err);
+    return { success: false, error: err.message || "Failed to create external user" };
+  }
+}
+
 export async function updateUserPassword(
   userId: number,
   newPassword: string,
diff --git a/README.md b/README.md
index 43d7f0b..be98675 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,8 @@ Docker is the easiest way to run it.
 - [No Docker (.bat / .sh)](#no-docker-bat--sh)
 - [Production Package Scripts](#production-package-scripts)
 - [WebRTC Streaming](#webrtc-streaming)
+- [OIDC / SSO Login](#oidc--sso-login)
+- [Login Branding](#login-branding)
 - [Docker Notes (TLS, reverse proxy, cache)](#docker-notes-tls-reverse-proxy-cache)
 
 ---
@@ -402,6 +404,53 @@ The compose file passes a minimal set of `MTX_*` environment variables to MediaM
 
 ---
 
+## OIDC / SSO Login
+
+Overlord supports generic OIDC login for homelab identity providers such as Authentik, Authelia, Keycloak, Zitadel, and Dex. Local username/password login stays enabled as a fallback.
+
+Configure your OIDC provider with this redirect URI:
+
+```text
+https://YOUR_OVERLORD_HOST/api/oidc/callback
+```
+
+Then set the relevant environment variables:
+
+```env
+OVERLORD_OIDC_ENABLED=true
+OVERLORD_OIDC_LABEL=Sign in with SSO
+OVERLORD_OIDC_ISSUER=https://auth.example.com/application/o/overlord/
+OVERLORD_OIDC_CLIENT_ID=overlord
+OVERLORD_OIDC_CLIENT_SECRET=change-me
+OVERLORD_OIDC_REDIRECT_URI=https://overlord.example.com/api/oidc/callback
+OVERLORD_OIDC_DEFAULT_ROLE=viewer
+OVERLORD_OIDC_ALLOWED_DOMAINS=example.com
+OVERLORD_OIDC_ADMIN_GROUPS=overlord-admins
+OVERLORD_OIDC_OPERATOR_GROUPS=overlord-operators
+OVERLORD_OIDC_VIEWER_GROUPS=overlord-viewers
+```
+
+New OIDC users are linked by the provider's `issuer + sub` identity. Email/username linking to an existing local account is disabled by default; enable `OVERLORD_OIDC_ALLOW_EMAIL_LINK=true` only if you trust your provider's verified email claims.
+
+---
+
+## Login Branding
+
+Self-hosted and enterprise deployments can brand the login screen with environment variables:
+
+```env
+OVERLORD_LOGIN_BRAND_NAME=Acme SOC
+OVERLORD_LOGIN_TITLE=Welcome to Acme Overlord
+OVERLORD_LOGIN_SUBTITLE=Sign in with your Acme identity
+OVERLORD_LOGIN_LOGO_URL=/assets/acme-logo.png
+OVERLORD_LOGIN_LOGO_ALT=Acme logo
+OVERLORD_LOGIN_ICON_CLASS=fa-solid fa-shield-halved
+```
+
+`OVERLORD_LOGIN_LOGO_URL` accepts absolute `http(s)` URLs or root-relative paths. If no logo URL is set, the login screen uses `OVERLORD_LOGIN_ICON_CLASS`.
+
+---
+
 ## Docker Notes (TLS, reverse proxy, cache)
 
 Notes on configs and workarounds.