diff --git a/Overlord-Server/public/assets/data.js b/Overlord-Server/public/assets/data.js
index 46c7f5f..72a11ad 100644
--- a/Overlord-Server/public/assets/data.js
+++ b/Overlord-Server/public/assets/data.js
@@ -57,6 +57,7 @@ export async function loadWithOptions(options = {}) {
       status: state.filterStatus || "all",
       os: state.filterOs || "all",
       country: state.filterCountry || "all",
+      group: state.filterGroup || "all",
     });
     const res = await fetch(`/api/clients?${params.toString()}`);
     if (!res.ok) throw new Error(`status ${res.status}`);
diff --git a/Overlord-Server/public/assets/main.css b/Overlord-Server/public/assets/main.css
index 299b651..15f332f 100644
--- a/Overlord-Server/public/assets/main.css
+++ b/Overlord-Server/public/assets/main.css
@@ -1781,7 +1781,7 @@ mark.search-current {
 #grid article.card {
   position: relative;
   overflow: hidden;
-  border-color: rgba(71, 85, 105, 0.55) !important;
+  border-color: var(--group-color, rgba(71, 85, 105, 0.55)) !important;
   backdrop-filter: blur(4px);
   transition:
     transform 170ms ease,
@@ -1791,10 +1791,11 @@ mark.search-current {
 
 #grid article.card:hover {
   transform: translateY(-2px);
-  border-color: rgba(99, 102, 241, 0.45) !important;
+  border-color: var(--group-color, rgba(99, 102, 241, 0.45)) !important;
   box-shadow:
     0 18px 36px rgba(2, 6, 23, 0.45),
-    0 0 0 1px rgba(99, 102, 241, 0.14);
+    0 0 0 1px color-mix(in srgb, var(--group-color, rgba(99, 102, 241, 0.14)) 40%, transparent),
+    0 0 20px 4px color-mix(in srgb, var(--group-color, transparent) 30%, transparent);
 }
 
 /* Cohesive UI polish layer */
diff --git a/Overlord-Server/public/assets/main.js b/Overlord-Server/public/assets/main.js
index 2c75bf2..351c508 100644
--- a/Overlord-Server/public/assets/main.js
+++ b/Overlord-Server/public/assets/main.js
@@ -22,6 +22,7 @@ const searchInput = document.getElementById("search");
 const sortSelect = document.getElementById("sort");
 const filterStatusSelect = document.getElementById("filter-status");
 const filterOsSelect = document.getElementById("filter-os");
+const filterGroupSelect = document.getElementById("filter-group");
 const showOfflineToggle = document.getElementById("toggle-offline");
 const selectAllBtn = document.getElementById("select-all");
 const clearSelectionBtn = document.getElementById("clear-selection");
@@ -45,6 +46,7 @@ const PREF_FILTER_STATUS_KEY = "overlord_filter_status";
 const PREF_SORT_KEY = "overlord_sort";
 const PREF_FILTER_OS_KEY = "overlord_filter_os";
 const PREF_FILTER_COUNTRY_KEY = "overlord_filter_country";
+const PREF_FILTER_GROUP_KEY = "overlord_filter_group";
 
 let currentUser = null;
 let contextCard = null;
@@ -498,6 +500,7 @@ function initializeRenderer() {
     userRole: currentUser?.role,
   });
   registerRenderer(renderMerge);
+  refreshGroupFilter();
   loadWithOptions();
   startAutoRefresh();
 
@@ -588,6 +591,14 @@ filterOsSelect?.addEventListener("change", (e) => {
   loadWithOptions({ force: true, reorder: true });
 });
 
+filterGroupSelect?.addEventListener("change", (e) => {
+  state.filterGroup = e.target.value;
+  localStorage.setItem(PREF_FILTER_GROUP_KEY, state.filterGroup);
+  state.page = 1;
+  state.lastDigest = "";
+  loadWithOptions({ force: true, reorder: true });
+});
+
 initCountryPicker((code) => {
   state.filterCountry = code;
   localStorage.setItem(PREF_FILTER_COUNTRY_KEY, code);
@@ -607,7 +618,7 @@ initCountryPicker((code) => {
   }
 
   const savedSort = localStorage.getItem(PREF_SORT_KEY);
-  const validSorts = ["stable", "last_seen_desc", "host_asc", "ping_asc", "ping_desc", "country_asc", "country_desc"];
+  const validSorts = ["stable", "last_seen_desc", "host_asc", "ping_asc", "ping_desc", "country_asc", "country_desc", "group_asc", "group_desc"];
   if (savedSort && validSorts.includes(savedSort)) {
     state.sort = savedSort;
     if (sortSelect) sortSelect.value = savedSort;
@@ -623,6 +634,12 @@ initCountryPicker((code) => {
   if (savedCountry) {
     state.filterCountry = savedCountry;
   }
+
+  const savedGroup = localStorage.getItem(PREF_FILTER_GROUP_KEY);
+  if (savedGroup) {
+    state.filterGroup = savedGroup;
+    if (filterGroupSelect) filterGroupSelect.value = savedGroup;
+  }
 })();
 
 showOfflineToggle?.addEventListener("change", (e) => {
@@ -834,6 +851,148 @@ window.setClientTag = async (clientId, tag, note) => {
   }
 };
 
+window.setClientGroup = async (clientId, groupId) => {
+  if (!clientId) return false;
+  try {
+    const res = await fetch(`/api/clients/${clientId}/group`, {
+      method: "PATCH",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ groupId }),
+    });
+    if (!res.ok) {
+      const data = await res.json().catch(() => ({}));
+      alert(data.error || "Failed to update client group");
+      return false;
+    }
+    return true;
+  } catch (err) {
+    console.error(err);
+    alert("Failed to update client group");
+    return false;
+  }
+};
+
+async function loadGroups() {
+  try {
+    const res = await fetch("/api/groups");
+    if (!res.ok) return [];
+    const data = await res.json();
+    return data.groups || [];
+  } catch { return []; }
+}
+
+async function refreshGroupFilter() {
+  const groups = await loadGroups();
+  if (!filterGroupSelect) return groups;
+  const current = filterGroupSelect.value;
+  filterGroupSelect.innerHTML = '<option value="all">All Groups</option><option value="none">No Group</option>';
+  groups.forEach((g) => {
+    const opt = document.createElement("option");
+    opt.value = String(g.id);
+    opt.textContent = g.name;
+    opt.style.color = g.color;
+    filterGroupSelect.appendChild(opt);
+  });
+  filterGroupSelect.value = current;
+  return groups;
+}
+
+async function openGroupPicker(clientId) {
+  const groups = await loadGroups();
+  const card = getClientCard(clientId);
+  const currentGroupId = card?.dataset.groupId || "";
+
+  const overlay = document.createElement("div");
+  overlay.className = "fixed inset-0 z-[10000] flex items-center justify-center bg-black/60";
+  overlay.addEventListener("click", (e) => { if (e.target === overlay) overlay.remove(); });
+
+  const modal = document.createElement("div");
+  modal.className = "bg-slate-900 border border-slate-700 rounded-xl shadow-2xl p-6 w-[400px] max-h-[80vh] flex flex-col gap-4";
+  modal.innerHTML = `
+    <h3 class="text-lg font-semibold text-slate-100 flex items-center gap-2"><i class="fa-solid fa-layer-group text-blue-400"></i> Set Group</h3>
+    <div class="group-picker-list flex flex-col gap-1 overflow-y-auto max-h-60"></div>
+    <div class="border-t border-slate-700 pt-3">
+      <p class="text-xs text-slate-400 mb-2">Create new group</p>
+      <div class="flex gap-2">
+        <input type="text" class="group-new-name flex-1 bg-slate-800 border border-slate-700 rounded-lg px-3 py-2 text-sm text-slate-100 outline-none focus:border-blue-500" placeholder="Group name" maxlength="64" />
+        <input type="color" class="group-new-color w-10 h-10 rounded-lg border border-slate-700 bg-slate-800 cursor-pointer" value="#3b82f6" />
+        <button class="group-create-btn px-3 py-2 rounded-lg bg-blue-600 hover:bg-blue-500 text-white text-sm font-medium">Create</button>
+      </div>
+    </div>
+  `;
+
+  const listEl = modal.querySelector(".group-picker-list");
+
+  function renderList() {
+    listEl.innerHTML = "";
+    const noneBtn = document.createElement("button");
+    noneBtn.className = `w-full text-left px-3 py-2 rounded-lg text-sm flex items-center gap-2 transition-colors ${!currentGroupId ? "bg-slate-700 text-white" : "text-slate-300 hover:bg-slate-800"}`;
+    noneBtn.innerHTML = '<i class="fa-solid fa-xmark text-slate-500"></i> No Group';
+    noneBtn.addEventListener("click", async () => {
+      const ok = await window.setClientGroup(clientId, null);
+      if (ok) setTimeout(() => loadWithOptions({ force: true }), 200);
+      overlay.remove();
+    });
+    listEl.appendChild(noneBtn);
+
+    groups.forEach((g) => {
+      const btn = document.createElement("button");
+      const isActive = String(g.id) === currentGroupId;
+      btn.className = `w-full text-left px-3 py-2 rounded-lg text-sm flex items-center gap-2 transition-colors ${isActive ? "bg-slate-700 text-white" : "text-slate-300 hover:bg-slate-800"}`;
+      btn.innerHTML = `<span class="inline-block w-3 h-3 rounded-full flex-shrink-0" style="background:${g.color}"></span> ${escapeHtml(g.name)}`;
+      btn.addEventListener("click", async () => {
+        const ok = await window.setClientGroup(clientId, g.id);
+        if (ok) setTimeout(() => loadWithOptions({ force: true }), 200);
+        overlay.remove();
+      });
+      listEl.appendChild(btn);
+    });
+  }
+
+  renderList();
+
+  const createBtn = modal.querySelector(".group-create-btn");
+  createBtn.addEventListener("click", async () => {
+    const nameInput = modal.querySelector(".group-new-name");
+    const colorInput = modal.querySelector(".group-new-color");
+    const name = nameInput.value.trim();
+    const color = colorInput.value;
+    if (!name) { nameInput.focus(); return; }
+    try {
+      const res = await fetch("/api/groups", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({ name, color }),
+      });
+      if (!res.ok) {
+        const d = await res.json().catch(() => ({}));
+        alert(d.error || "Failed to create group");
+        return;
+      }
+      const newGroup = await res.json();
+      groups.push(newGroup);
+      nameInput.value = "";
+      renderList();
+      refreshGroupFilter();
+    } catch (err) {
+      console.error(err);
+      alert("Failed to create group");
+    }
+  });
+
+  overlay.appendChild(modal);
+  document.body.appendChild(overlay);
+  modal.querySelector(".group-new-name").addEventListener("keydown", (e) => {
+    if (e.key === "Enter") createBtn.click();
+  });
+}
+
+function escapeHtml(text) {
+  const div = document.createElement("div");
+  div.textContent = text;
+  return div.innerHTML;
+}
+
 window.banClient = async (clientId) => {
   if (!clientId) return;
   if (!confirm(`Ban IP for ${clientId} and block future connections?`)) return;
@@ -1068,6 +1227,11 @@ menu.addEventListener("click", async (e) => {
     }
     closeMenu(clearContext);
     return;
+  } else if (action === "set-group") {
+    const savedClientId = contextCard;
+    closeMenu(clearContext);
+    openGroupPicker(savedClientId);
+    return;
   }
 
   if (!isClientOnline(contextCard)) {
diff --git a/Overlord-Server/public/assets/render.js b/Overlord-Server/public/assets/render.js
index 5d858a8..94ef69c 100644
--- a/Overlord-Server/public/assets/render.js
+++ b/Overlord-Server/public/assets/render.js
@@ -16,7 +16,7 @@ function escapeHtml(text) {
 }
 
 function cardDigest(c) {
-  return `${c.id}|${!!c.online}|${c.lastSeen}|${c.pingMs}|${c.host}|${c.user}|${c.os}|${c.arch}|${c.version}|${c.monitors}|${c.thumbnail}|${c.country}|${c.nickname}|${c.customTag}|${c.customTagNote}|${!!c.bookmarked}|${!!c.isAdmin}|${c.elevation}|${c.cpu}|${c.gpu}|${c.ram}|${c.hwid}|${c.disconnectReason}|${c.disconnectDetail}|${JSON.stringify(c.permissions)}`;
+  return `${c.id}|${!!c.online}|${c.lastSeen}|${c.pingMs}|${c.host}|${c.user}|${c.os}|${c.arch}|${c.version}|${c.monitors}|${c.thumbnail}|${c.country}|${c.nickname}|${c.customTag}|${c.customTagNote}|${!!c.bookmarked}|${!!c.isAdmin}|${c.elevation}|${c.cpu}|${c.gpu}|${c.ram}|${c.hwid}|${c.disconnectReason}|${c.disconnectDetail}|${JSON.stringify(c.permissions)}|${c.groupId}|${c.groupName}|${c.groupColor}`;
 }
 
 export function createRenderer({
@@ -373,6 +373,9 @@ export function createRenderer({
     card.dataset.customTag = String(client.customTag || "");
     card.dataset.bookmarked = String(!!client.bookmarked);
     card.dataset.admin = String(!!client.isAdmin);
+    card.dataset.groupId = String(client.groupId || "");
+    card.dataset.groupName = String(client.groupName || "");
+    card.dataset.groupColor = String(client.groupColor || "");
     card._customTagNote = String(client.customTagNote || "");
     const os = osBadge(client.os || "unknown");
     const arch = archBadge(client.arch || "");
@@ -387,6 +390,8 @@ export function createRenderer({
     const hasTagNote = customTag.length > 0 && customTagNote.length > 0;
     const isTagNoteExpanded = hasTagNote && wasTagNoteExpanded;
     card.dataset.tagNoteExpanded = isTagNoteExpanded ? "true" : "false";
+    const groupName = String(client.groupName || "").trim();
+    const groupColor = String(client.groupColor || "").trim();
     const hasHwInfo = !!(client.cpu || client.gpu || client.ram);
     const isHwExpanded = hasHwInfo && wasHwExpanded;
     card.dataset.hwExpanded = isHwExpanded ? "true" : "false";
@@ -397,7 +402,13 @@ export function createRenderer({
       return [...counts.entries()].map(([name, n]) => n > 1 ? `${name} <span class="hw-gpu-count">&times;${n}</span>` : escapeHtml(name)).join(", ");
     };
     const gpuHtml = dedupeGpu(client.gpu);
-    card.className = `card rounded-xl border ${client.bookmarked ? "border-yellow-600/60" : "border-slate-800"} bg-slate-900/70 p-4 shadow-lg ${client.online ? "" : "card-offline"} tone-${os.tone}`;
+    const borderClass = client.bookmarked ? "border-yellow-600/60" : "border-slate-800";
+    card.className = `card rounded-xl border ${borderClass} bg-slate-900/70 p-4 shadow-lg ${client.online ? "" : "card-offline"} tone-${os.tone}`;
+    if (!client.bookmarked && groupColor) {
+      card.style.setProperty("--group-color", groupColor);
+    } else {
+      card.style.removeProperty("--group-color");
+    }
     const cardThumb = client.thumbnail
       ? (() => {
           const wrapper = document.createElement("div");
@@ -429,6 +440,7 @@ export function createRenderer({
             <span>${escapeHtml(displayName)}</span>
             ${nickname && client.host ? `<span class="pill pill-ghost text-xs"><i class="fa-solid fa-laptop"></i> ${escapeHtml(client.host)}</span>` : ""}
             ${customTag ? `<button type="button" class="client-tag-toggle pill text-xs border border-amber-700/80 bg-amber-900/30 text-amber-200 ${hasTagNote ? "cursor-pointer hover:bg-amber-800/40" : "cursor-default opacity-90"}" ${hasTagNote ? `aria-expanded="${isTagNoteExpanded ? "true" : "false"}"` : `disabled aria-disabled="true"`}><i class="fa-solid fa-tag"></i> ${escapeHtml(customTag)} ${customTagNote ? `<i class="fa-regular fa-note-sticky"></i><i class="fa-solid ${isTagNoteExpanded ? "fa-chevron-up" : "fa-chevron-down"}"></i>` : ""}</button>` : ""}
+            ${groupName ? `<span class="pill text-xs border" style="border-color:${escapeHtml(groupColor)};background:${escapeHtml(groupColor)}22;color:${escapeHtml(groupColor)}"><i class="fa-solid fa-layer-group"></i> ${escapeHtml(groupName)}</span>` : ""}
             <span class="text-slate-300 text-lg font-semibold flex items-center gap-1"><i class="fa-solid fa-user"></i> ${escapeHtml(client.user || "unknown")}</span>
             <span class="pill ${client.online ? "pill-online" : "pill-offline"}">
               <i class="fa-solid fa-circle"></i>
diff --git a/Overlord-Server/public/assets/state.js b/Overlord-Server/public/assets/state.js
index 9b31748..f53f0ac 100644
--- a/Overlord-Server/public/assets/state.js
+++ b/Overlord-Server/public/assets/state.js
@@ -6,6 +6,7 @@ export const state = {
   filterStatus: "all",
   filterOs: "all",
   filterCountry: "all",
+  filterGroup: "all",
   lastDigest: "",
   isLoading: false,
   pendingForce: false,
diff --git a/Overlord-Server/public/assets/ui.js b/Overlord-Server/public/assets/ui.js
index 1530b92..bb95310 100644
--- a/Overlord-Server/public/assets/ui.js
+++ b/Overlord-Server/public/assets/ui.js
@@ -44,6 +44,7 @@ const MENU_GROUPS = [
       { label: "Reconnect",             icon: "fa-solid fa-rotate",            icolor: "text-slate-300", action: "reconnect" },
       { label: "Set Nickname",          icon: "fa-solid fa-signature",         icolor: "text-slate-300", action: "set-nickname" },
       { label: "Set Custom Tag",        icon: "fa-solid fa-tag",               icolor: "text-slate-300", action: "set-custom-tag" },
+      { label: "Set Group",              icon: "fa-solid fa-layer-group",       icolor: "text-blue-300",  action: "set-group" },
       { divider: true },
       { label: "Elevate (macOS)",       icon: "fa-solid fa-arrow-up-right-dots", icolor: "text-green-400", action: "elevate" },
       { divider: true },
diff --git a/Overlord-Server/public/index.html b/Overlord-Server/public/index.html
index 96622be..b731efd 100644
--- a/Overlord-Server/public/index.html
+++ b/Overlord-Server/public/index.html
@@ -88,6 +88,13 @@
           >
             <option value="all">All OS</option>
           </select>
+          <select
+            id="filter-group"
+            class="bg-slate-900/70 border border-slate-800 rounded-lg px-3 py-2 text-slate-100"
+          >
+            <option value="all">All Groups</option>
+            <option value="none">No Group</option>
+          </select>
           <div id="country-picker-anchor" class="relative"></div>
           <select
             id="sort"
@@ -100,6 +107,8 @@
             <option value="ping_desc">Ping ↓</option>
             <option value="country_asc">Country A→Z</option>
             <option value="country_desc">Country Z→A</option>
+            <option value="group_asc">Group A→Z</option>
+            <option value="group_desc">Group Z→A</option>
             <option value="admin_first">Admin first</option>
           </select>
           <button
diff --git a/Overlord-Server/src/db.ts b/Overlord-Server/src/db.ts
index ba1b21e..726ca22 100644
--- a/Overlord-Server/src/db.ts
+++ b/Overlord-Server/src/db.ts
@@ -124,6 +124,20 @@ try {
   db.run(`ALTER TABLE clients ADD COLUMN permissions TEXT`);
 } catch {}
 
+db.run(`
+  CREATE TABLE IF NOT EXISTS client_groups (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name TEXT UNIQUE NOT NULL,
+    color TEXT NOT NULL DEFAULT '#3b82f6',
+    created_at INTEGER NOT NULL
+  );
+`);
+
+try {
+  db.run(`ALTER TABLE clients ADD COLUMN group_id INTEGER REFERENCES client_groups(id) ON DELETE SET NULL`);
+} catch {}
+db.run(`CREATE INDEX IF NOT EXISTS idx_clients_group_id ON clients(group_id);`);
+
 db.run(`
   CREATE TABLE IF NOT EXISTS banned_ips (
     ip TEXT PRIMARY KEY,
@@ -589,6 +603,75 @@ export function setClientTag(
   return ((result as any)?.changes || 0) > 0;
 }
 
+export interface ClientGroup {
+  id: number;
+  name: string;
+  color: string;
+  createdAt: number;
+  clientCount?: number;
+}
+
+export function listGroups(): ClientGroup[] {
+  const rows = db.query<any>(
+    `SELECT g.id, g.name, g.color, g.created_at as createdAt,
+            COUNT(c.id) as clientCount
+     FROM client_groups g
+     LEFT JOIN clients c ON c.group_id = g.id
+     GROUP BY g.id
+     ORDER BY g.name ASC`,
+  ).all();
+  return rows.map((r: any) => ({
+    id: r.id,
+    name: r.name,
+    color: r.color,
+    createdAt: r.createdAt,
+    clientCount: r.clientCount ?? 0,
+  }));
+}
+
+export function getGroup(id: number): ClientGroup | null {
+  const row = db.query<any>(
+    `SELECT id, name, color, created_at as createdAt FROM client_groups WHERE id=?`,
+  ).get(id);
+  return row ? { id: row.id, name: row.name, color: row.color, createdAt: row.createdAt } : null;
+}
+
+export function createGroup(name: string, color: string): ClientGroup {
+  const now = Date.now();
+  const result = db.run(
+    `INSERT INTO client_groups (name, color, created_at) VALUES (?, ?, ?)`,
+    name.trim(),
+    color,
+    now,
+  );
+  return { id: Number(result.lastInsertRowid), name: name.trim(), color, createdAt: now };
+}
+
+export function updateGroup(id: number, name: string, color: string): boolean {
+  const result = db.run(
+    `UPDATE client_groups SET name=?, color=? WHERE id=?`,
+    name.trim(),
+    color,
+    id,
+  );
+  return ((result as any)?.changes || 0) > 0;
+}
+
+export function deleteGroup(id: number): boolean {
+  db.run(`UPDATE clients SET group_id=NULL WHERE group_id=?`, id);
+  const result = db.run(`DELETE FROM client_groups WHERE id=?`, id);
+  return ((result as any)?.changes || 0) > 0;
+}
+
+export function setClientGroup(clientId: string, groupId: number | null): boolean {
+  const result = db.run(
+    `UPDATE clients SET group_id=? WHERE id=?`,
+    groupId,
+    clientId,
+  );
+  return ((result as any)?.changes || 0) > 0;
+}
+
 export function getClientIp(id: string): string | null {
   const row = db.query<{ ip: string }>(`SELECT ip FROM clients WHERE id=?`).get(id);
   return row?.ip || null;
@@ -798,107 +881,125 @@ export function listClients(filters: ListFilters): ListResult {
     requireBuildOwner,
     allowedClientIds,
     deniedClientIds,
+    groupFilter,
   } = filters;
   const where: string[] = [];
   const params: any[] = [];
 
   if (search) {
     where.push(
-      "(LOWER(COALESCE(host,'')) LIKE ? OR LOWER(COALESCE(user,'')) LIKE ? OR LOWER(COALESCE(nickname,'')) LIKE ? OR LOWER(COALESCE(custom_tag,'')) LIKE ? OR LOWER(COALESCE(custom_tag_note,'')) LIKE ? OR LOWER(id) LIKE ?)",
+      "(LOWER(COALESCE(c.host,'')) LIKE ? OR LOWER(COALESCE(c.user,'')) LIKE ? OR LOWER(COALESCE(c.nickname,'')) LIKE ? OR LOWER(COALESCE(c.custom_tag,'')) LIKE ? OR LOWER(COALESCE(c.custom_tag_note,'')) LIKE ? OR LOWER(c.id) LIKE ? OR LOWER(COALESCE(g.name,'')) LIKE ?)",
     );
     const needle = `%${search}%`;
-    params.push(needle, needle, needle, needle, needle, needle);
+    params.push(needle, needle, needle, needle, needle, needle, needle);
   }
 
   if (statusFilter === "online") {
-    where.push("online=1");
+    where.push("c.online=1");
   } else if (statusFilter === "offline") {
-    where.push("online=0");
+    where.push("c.online=0");
   }
 
   if (enrollmentFilter && enrollmentFilter !== "all") {
     if (enrollmentFilter === "pending") {
-      where.push("(enrollment_status='pending' OR enrollment_status IS NULL)");
+      where.push("(c.enrollment_status='pending' OR c.enrollment_status IS NULL)");
     } else {
-      where.push("enrollment_status=?");
+      where.push("c.enrollment_status=?");
       params.push(enrollmentFilter);
     }
   }
 
   if (osFilter && osFilter !== "all") {
-    where.push("os=?");
+    where.push("c.os=?");
     params.push(osFilter);
   }
 
   if (countryFilter && countryFilter !== "all") {
-    where.push("UPPER(COALESCE(country,'ZZ'))=?");
+    where.push("UPPER(COALESCE(c.country,'ZZ'))=?");
     params.push(countryFilter.toUpperCase());
   }
 
   if (typeof builtByUserId === "number") {
-    where.push("built_by_user_id=?");
+    where.push("c.built_by_user_id=?");
     params.push(builtByUserId);
   }
 
   if (requireBuildOwner) {
-    where.push("built_by_user_id IS NOT NULL");
+    where.push("c.built_by_user_id IS NOT NULL");
   }
 
   if (Array.isArray(allowedClientIds)) {
     if (allowedClientIds.length === 0) {
       where.push("1=0");
     } else {
-      where.push(`id IN (${allowedClientIds.map(() => "?").join(",")})`);
+      where.push(`c.id IN (${allowedClientIds.map(() => "?").join(",")})`);
       params.push(...allowedClientIds);
     }
   }
 
   if (Array.isArray(deniedClientIds) && deniedClientIds.length > 0) {
-    where.push(`id NOT IN (${deniedClientIds.map(() => "?").join(",")})`);
+    where.push(`c.id NOT IN (${deniedClientIds.map(() => "?").join(",")})`);
     params.push(...deniedClientIds);
   }
 
+  if (groupFilter && groupFilter !== "all") {
+    if (groupFilter === "none") {
+      where.push("c.group_id IS NULL");
+    } else {
+      const gid = Number(groupFilter);
+      if (Number.isFinite(gid)) {
+        where.push("c.group_id=?");
+        params.push(gid);
+      }
+    }
+  }
+
   const whereSql = where.length ? `WHERE ${where.join(" AND ")}` : "";
 
   const orderBy = (() => {
-    const online = "online DESC";
-    const bookmark = "bookmarked DESC";
+    const online = "c.online DESC";
+    const bookmark = "c.bookmarked DESC";
     switch (sort) {
       case "stable":
-        return `ORDER BY ${online}, ${bookmark}, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, c.id ASC`;
       case "ping_asc":
-        return `ORDER BY ${online}, ${bookmark}, ping_ms IS NULL, ping_ms ASC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, c.ping_ms IS NULL, c.ping_ms ASC, c.id ASC`;
       case "ping_desc":
-        return `ORDER BY ${online}, ${bookmark}, ping_ms IS NULL, ping_ms DESC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, c.ping_ms IS NULL, c.ping_ms DESC, c.id ASC`;
       case "host_asc":
-        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(nickname, host)) ASC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(c.nickname, c.host)) ASC, c.id ASC`;
       case "host_desc":
-        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(nickname, host)) DESC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(c.nickname, c.host)) DESC, c.id ASC`;
       case "country_asc":
-        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(country, 'zz')) ASC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(c.country, 'zz')) ASC, c.id ASC`;
       case "country_desc":
-        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(country, 'zz')) DESC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, LOWER(COALESCE(c.country, 'zz')) DESC, c.id ASC`;
       case "admin_first":
-        return `ORDER BY ${online}, ${bookmark}, is_admin DESC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, c.is_admin DESC, c.id ASC`;
+      case "group_asc":
+        return `ORDER BY ${online}, ${bookmark}, g.name IS NULL, LOWER(g.name) ASC, c.id ASC`;
+      case "group_desc":
+        return `ORDER BY ${online}, ${bookmark}, g.name IS NULL, LOWER(g.name) DESC, c.id ASC`;
       default:
-        return `ORDER BY ${online}, ${bookmark}, last_seen DESC, id ASC`;
+        return `ORDER BY ${online}, ${bookmark}, c.last_seen DESC, c.id ASC`;
     }
   })();
 
   const totalRow = db
-    .query<{ c: number }>(`SELECT COUNT(*) as c FROM clients ${whereSql}`)
+    .query<{ c: number }>(`SELECT COUNT(*) as c FROM clients c LEFT JOIN client_groups g ON g.id = c.group_id ${whereSql}`)
     .get(...params) ?? { c: 0 };
   const onlineRow = db
     .query<{ c: number }>(
-      `SELECT COUNT(*) as c FROM clients ${whereSql ? `${whereSql} AND online=1` : "WHERE online=1"}`,
+      `SELECT COUNT(*) as c FROM clients c LEFT JOIN client_groups g ON g.id = c.group_id ${whereSql ? `${whereSql} AND c.online=1` : "WHERE c.online=1"}`,
     )
     .get(...params) ?? { c: 0 };
   const offset = (page - 1) * pageSize;
 
   const rows = db
     .query<any>(
-      `SELECT id, hwid, role, ip, host, os, arch, version, user, nickname, custom_tag as customTag, custom_tag_note as customTagNote, monitors, country, last_seen as lastSeen, online, ping_ms as pingMs, bookmarked, build_tag as buildTag, built_by_user_id as builtByUserId, enrollment_status as enrollmentStatus, public_key as publicKey, key_fingerprint as keyFingerprint, cpu, gpu, ram, is_admin as isAdmin, elevation, permissions, disconnect_reason as disconnectReason, disconnect_detail as disconnectDetail
-       FROM clients
+      `SELECT c.id, c.hwid, c.role, c.ip, c.host, c.os, c.arch, c.version, c.user, c.nickname, c.custom_tag as customTag, c.custom_tag_note as customTagNote, c.monitors, c.country, c.last_seen as lastSeen, c.online, c.ping_ms as pingMs, c.bookmarked, c.build_tag as buildTag, c.built_by_user_id as builtByUserId, c.enrollment_status as enrollmentStatus, c.public_key as publicKey, c.key_fingerprint as keyFingerprint, c.cpu, c.gpu, c.ram, c.is_admin as isAdmin, c.elevation, c.permissions, c.disconnect_reason as disconnectReason, c.disconnect_detail as disconnectDetail, c.group_id as groupId, g.name as groupName, g.color as groupColor
+       FROM clients c
+       LEFT JOIN client_groups g ON g.id = c.group_id
        ${whereSql}
        ${orderBy}
        LIMIT ? OFFSET ?`,
@@ -937,6 +1038,9 @@ export function listClients(filters: ListFilters): ListResult {
     permissions: c.permissions ? (() => { try { return JSON.parse(c.permissions); } catch { return null; } })() : null,
     disconnectReason: c.disconnectReason || null,
     disconnectDetail: c.disconnectDetail || null,
+    groupId: typeof c.groupId === "number" ? c.groupId : null,
+    groupName: c.groupName || null,
+    groupColor: c.groupColor || null,
     thumbnail: getThumbnail(c.id),
   }));
 
diff --git a/Overlord-Server/src/server/routes/client-routes.ts b/Overlord-Server/src/server/routes/client-routes.ts
index a9e3243..44a1e05 100644
--- a/Overlord-Server/src/server/routes/client-routes.ts
+++ b/Overlord-Server/src/server/routes/client-routes.ts
@@ -18,6 +18,12 @@ import {
   setClientTag,
   setOnlineState,
   unbanIp,
+  listGroups,
+  getGroup,
+  createGroup,
+  updateGroup,
+  deleteGroup,
+  setClientGroup,
 } from "../../db";
 import { metrics } from "../../metrics";
 import { encodeMessage } from "../../protocol";
@@ -59,6 +65,7 @@ export async function handleClientRoutes(
 ): Promise<Response | null> {
   if (
     !url.pathname.startsWith("/api/clients") &&
+    !url.pathname.startsWith("/api/groups") &&
     !url.pathname.match(/^\/api\/clients\/.+\/command$/)
   ) {
     return null;
@@ -77,9 +84,10 @@ export async function handleClientRoutes(
     const osFilter = url.searchParams.get("os") || "all";
     const countryFilter = url.searchParams.get("country") || "all";
     const enrollmentFilter = url.searchParams.get("enrollmentFilter") || "approved";
+    const groupFilter = url.searchParams.get("group") || "all";
     const isEnrollmentRequest = url.searchParams.has("enrollmentFilter");
     if (user.role === "admin") {
-      const result = listClients({ page, pageSize, search, sort, statusFilter, osFilter, countryFilter, enrollmentFilter });
+      const result = listClients({ page, pageSize, search, sort, statusFilter, osFilter, countryFilter, enrollmentFilter, groupFilter });
       return Response.json(result, { headers: deps.CORS_HEADERS });
     }
 
@@ -93,6 +101,7 @@ export async function handleClientRoutes(
         osFilter,
         countryFilter,
         enrollmentFilter,
+        groupFilter,
         builtByUserId: user.userId,
         requireBuildOwner: true,
       });
@@ -125,6 +134,7 @@ export async function handleClientRoutes(
       osFilter,
       countryFilter,
       enrollmentFilter,
+      groupFilter,
       allowedClientIds,
       deniedClientIds,
     });
@@ -758,5 +768,124 @@ export async function handleClientRoutes(
     }
   }
 
+  if (url.pathname === "/api/groups") {
+    const user = await authenticateRequest(req);
+    if (!user) return new Response("Unauthorized", { status: 401 });
+
+    if (req.method === "GET") {
+      return Response.json({ groups: listGroups() }, { headers: deps.CORS_HEADERS });
+    }
+
+    if (req.method === "POST") {
+      try { requirePermission(user, "clients:control"); } catch (error) {
+        if (error instanceof Response) return error;
+        return new Response("Forbidden", { status: 403 });
+      }
+
+      let body: any = {};
+      try { body = await req.json(); } catch {
+        return Response.json({ error: "Invalid JSON body" }, { status: 400 });
+      }
+
+      const name = typeof body?.name === "string" ? body.name.trim() : "";
+      const color = typeof body?.color === "string" ? body.color.trim() : "#3b82f6";
+      if (!name || name.length > 64) {
+        return Response.json({ error: "Name is required and must be 64 characters or fewer" }, { status: 400 });
+      }
+      if (!/^#[0-9a-fA-F]{6}$/.test(color)) {
+        return Response.json({ error: "Color must be a valid hex code (#RRGGBB)" }, { status: 400 });
+      }
+
+      const group = createGroup(name, color);
+      const ip = server.requestIP(req)?.address || "unknown";
+      logAudit({ timestamp: Date.now(), username: user.username, ip, action: AuditAction.COMMAND, details: `create_group:${name}`, success: true });
+      return Response.json(group, { status: 201, headers: deps.CORS_HEADERS });
+    }
+  }
+
+  const groupIdMatch = url.pathname.match(/^\/api\/groups\/(\d+)$/);
+  if (groupIdMatch) {
+    const user = await authenticateRequest(req);
+    if (!user) return new Response("Unauthorized", { status: 401 });
+    try { requirePermission(user, "clients:control"); } catch (error) {
+      if (error instanceof Response) return error;
+      return new Response("Forbidden", { status: 403 });
+    }
+
+    const groupId = Number(groupIdMatch[1]);
+
+    if (req.method === "PATCH") {
+      let body: any = {};
+      try { body = await req.json(); } catch {
+        return Response.json({ error: "Invalid JSON body" }, { status: 400 });
+      }
+
+      const existing = getGroup(groupId);
+      if (!existing) return Response.json({ error: "Group not found" }, { status: 404 });
+
+      const name = typeof body?.name === "string" ? body.name.trim() : existing.name;
+      const color = typeof body?.color === "string" ? body.color.trim() : existing.color;
+      if (name.length === 0 || name.length > 64) {
+        return Response.json({ error: "Name must be 1-64 characters" }, { status: 400 });
+      }
+      if (!/^#[0-9a-fA-F]{6}$/.test(color)) {
+        return Response.json({ error: "Color must be a valid hex code (#RRGGBB)" }, { status: 400 });
+      }
+
+      const updated = updateGroup(groupId, name, color);
+      if (!updated) return Response.json({ error: "Group not found" }, { status: 404 });
+      notifyDashboardViewers();
+      const ip = server.requestIP(req)?.address || "unknown";
+      logAudit({ timestamp: Date.now(), username: user.username, ip, action: AuditAction.COMMAND, details: `update_group:${groupId}`, success: true });
+      return Response.json({ ok: true, id: groupId, name, color }, { headers: deps.CORS_HEADERS });
+    }
+
+    if (req.method === "DELETE") {
+      const deleted = deleteGroup(groupId);
+      if (!deleted) return Response.json({ error: "Group not found" }, { status: 404 });
+      notifyDashboardViewers();
+      const ip = server.requestIP(req)?.address || "unknown";
+      logAudit({ timestamp: Date.now(), username: user.username, ip, action: AuditAction.COMMAND, details: `delete_group:${groupId}`, success: true });
+      return Response.json({ ok: true }, { headers: deps.CORS_HEADERS });
+    }
+  }
+
+  const clientGroupMatch = url.pathname.match(/^\/api\/clients\/([^/]+)\/group$/);
+  if (req.method === "PATCH" && clientGroupMatch) {
+    const user = await authenticateRequest(req);
+    if (!user) return new Response("Unauthorized", { status: 401 });
+    try { requirePermission(user, "clients:control"); } catch (error) {
+      if (error instanceof Response) return error;
+      return new Response("Forbidden", { status: 403 });
+    }
+
+    const targetId = clientGroupMatch[1];
+    if (!canUserAccessClient(user.userId, user.role, targetId)) {
+      return new Response("Forbidden: Client access denied", { status: 403 });
+    }
+    if (!clientExists(targetId)) {
+      return Response.json({ error: "Client not found" }, { status: 404 });
+    }
+
+    let body: any = {};
+    try { body = await req.json(); } catch {
+      return Response.json({ error: "Invalid JSON body" }, { status: 400 });
+    }
+
+    const groupId = body?.groupId === null ? null : Number(body?.groupId);
+    if (groupId !== null && (isNaN(groupId) || groupId < 1)) {
+      return Response.json({ error: "Invalid groupId" }, { status: 400 });
+    }
+
+    const updated = setClientGroup(targetId, groupId);
+    if (!updated) {
+      return Response.json({ error: "Client not found or group does not exist" }, { status: 404 });
+    }
+    notifyDashboardViewers();
+    const ip = server.requestIP(req)?.address || "unknown";
+    logAudit({ timestamp: Date.now(), username: user.username, ip, action: AuditAction.COMMAND, targetClientId: targetId, details: groupId ? `set_group:${groupId}` : "clear_group", success: true });
+    return Response.json({ ok: true, groupId }, { headers: deps.CORS_HEADERS });
+  }
+
   return null;
 }
diff --git a/Overlord-Server/src/types.ts b/Overlord-Server/src/types.ts
index 09ecff5..5a7a24b 100644
--- a/Overlord-Server/src/types.ts
+++ b/Overlord-Server/src/types.ts
@@ -38,6 +38,9 @@ export type ClientInfo = {
   keyFingerprint?: string;
   disconnectReason?: string;
   disconnectDetail?: string;
+  groupId?: number | null;
+  groupName?: string | null;
+  groupColor?: string | null;
 };
 
 export type ListFilters = {
@@ -53,6 +56,7 @@ export type ListFilters = {
   requireBuildOwner?: boolean;
   allowedClientIds?: string[];
   deniedClientIds?: string[];
+  groupFilter?: string;
 };
 
 export type ListItem = ClientInfo & {