diff --git a/backend/app/api/v1/routes_admin.py b/backend/app/api/v1/routes_admin.py
index f7bc80a..54949ce 100644
--- a/backend/app/api/v1/routes_admin.py
+++ b/backend/app/api/v1/routes_admin.py
@@ -62,7 +62,8 @@ async def list_users(
             role=user_doc["role"],
             auth_provider=user_doc.get("auth_provider", "local"),
             is_active=user_doc["is_active"],
-            created_at=user_doc.get("created_at", datetime.utcnow()).isoformat()
+            created_at=user_doc.get("created_at", datetime.utcnow()).isoformat(),
+            pm_client_ids=user_doc.get("pm_client_ids", []),
         ))
     
     return UserListResponse(
@@ -94,7 +95,8 @@ async def get_user(
         role=user_doc["role"],
         auth_provider=user_doc.get("auth_provider", "local"),
         is_active=user_doc["is_active"],
-        created_at=user_doc.get("created_at", datetime.utcnow()).isoformat()
+        created_at=user_doc.get("created_at", datetime.utcnow()).isoformat(),
+        pm_client_ids=user_doc.get("pm_client_ids", []),
     )
 
 
@@ -141,7 +143,8 @@ async def create_user(
         role=user_data.role,
         auth_provider="local",
         is_active=True,
-        created_at=user_doc["created_at"].isoformat()
+        created_at=user_doc["created_at"].isoformat(),
+        pm_client_ids=[],
     )
 
 
@@ -198,7 +201,8 @@ async def update_user(
         role=result["role"],
         auth_provider=result.get("auth_provider", "local"),
         is_active=result["is_active"],
-        created_at=result.get("created_at", datetime.utcnow()).isoformat()
+        created_at=result.get("created_at", datetime.utcnow()).isoformat(),
+        pm_client_ids=result.get("pm_client_ids", []),
     )
 
 
diff --git a/backend/app/schemas/auth.py b/backend/app/schemas/auth.py
index 11e6e1a..7d6bd11 100644
--- a/backend/app/schemas/auth.py
+++ b/backend/app/schemas/auth.py
@@ -53,6 +53,7 @@ class UserResponse(BaseModel):
     auth_provider: AuthProvider
     is_active: bool
     created_at: Optional[str] = None
+    pm_client_ids: list[str] = []
 
 
 class UserListResponse(BaseModel):
diff --git a/frontend/src/hooks/useClients.ts b/frontend/src/hooks/useClients.ts
index 6045cec..905239e 100644
--- a/frontend/src/hooks/useClients.ts
+++ b/frontend/src/hooks/useClients.ts
@@ -15,7 +15,7 @@ export function useClient(clientId: string) {
   return useQuery({
     queryKey: ['clients', clientId],
     queryFn: () => apiClient.getClient(clientId),
-    enabled: !!clientId,
+    enabled: !!clientId && clientId !== 'undefined',
   });
 }
 
@@ -39,6 +39,58 @@ export function useUpdateClient(clientId: string) {
   });
 }
 
+export function useTeamsForClient(clientId: string | null) {
+  return useQuery({
+    queryKey: ['clients', clientId, 'teams'],
+    queryFn: () => apiClient.listTeams(clientId!),
+    enabled: !!clientId,
+  });
+}
+
+export function useAssignPMAny() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({ clientId, userId }: { clientId: string; userId: string }) =>
+      apiClient.assignPM(clientId, userId),
+    onSuccess: (_, { clientId, userId }) => {
+      qc.invalidateQueries({ queryKey: ['clients', clientId, 'pm'] });
+      qc.invalidateQueries({ queryKey: ['users', userId] });
+      qc.invalidateQueries({ queryKey: ['users'] });
+    },
+  });
+}
+
+export function useRemovePMAny() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({ clientId, userId }: { clientId: string; userId: string }) =>
+      apiClient.removePM(clientId, userId),
+    onSuccess: (_, { clientId, userId }) => {
+      qc.invalidateQueries({ queryKey: ['clients', clientId, 'pm'] });
+      qc.invalidateQueries({ queryKey: ['users', userId] });
+      qc.invalidateQueries({ queryKey: ['users'] });
+    },
+  });
+}
+
+export function useAddTeamMemberAny() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({ clientId, teamId, userId }: { clientId: string; teamId: string; userId: string }) =>
+      apiClient.addTeamMember(clientId, teamId, userId),
+    onSuccess: (_, { clientId }) => qc.invalidateQueries({ queryKey: ['clients', clientId, 'teams'] }),
+  });
+}
+
+export function useRemoveTeamMemberAny() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({ clientId, teamId, userId }: { clientId: string; teamId: string; userId: string }) =>
+      apiClient.removeTeamMember(clientId, teamId, userId),
+    onSuccess: (_, { clientId }) => qc.invalidateQueries({ queryKey: ['clients', clientId, 'teams'] }),
+  });
+}
+
 // ── PMs ──────────────────────────────────────────────────────────────────────
 
 export function usePMs(clientId: string) {
diff --git a/frontend/src/routes/admin/UserDetail.tsx b/frontend/src/routes/admin/UserDetail.tsx
index 0021703..e2f9713 100644
--- a/frontend/src/routes/admin/UserDetail.tsx
+++ b/frontend/src/routes/admin/UserDetail.tsx
@@ -1,8 +1,17 @@
 import { useState, useEffect } from 'react';
 import { useParams, useNavigate, Link } from 'react-router-dom';
 import { useUser, useUpdateUser, useResetUserPassword } from '../../hooks/useUsers';
+import {
+  useClients,
+  useTeamsForClient,
+  useAssignPMAny,
+  useRemovePMAny,
+  useAddTeamMemberAny,
+  useRemoveTeamMemberAny,
+} from '../../hooks/useClients';
 import { useToastContext } from '../../contexts/ToastContext';
-import type { UserRole, UpdateUserRequest } from '../../types/api';
+import { useQueryClient } from '@tanstack/react-query';
+import type { UserRole, UpdateUserRequest, User, Client, Team } from '../../types/api';
 
 export function UserDetail() {
   const { id } = useParams<{ id: string }>();
@@ -20,7 +29,6 @@ export function UserDetail() {
     is_active: true,
   });
 
-  // Initialize form when user data loads
   useEffect(() => {
     if (user) {
       setFormData({
@@ -166,6 +174,7 @@ export function UserDetail() {
                 <option value="reviewer">Reviewer</option>
                 <option value="linguist">Linguist</option>
                 <option value="production">Production</option>
+                <option value="project_manager">Project Manager</option>
                 <option value="admin">Admin</option>
               </select>
             </div>
@@ -246,6 +255,9 @@ export function UserDetail() {
             </dl>
           </div>
 
+          {/* Assignments Card */}
+          <UserAssignmentsPanel user={user} />
+
           {/* Actions Card */}
           <div className="bg-white shadow rounded-lg p-6">
             <h3 className="text-lg font-medium text-gray-900 mb-4">Actions</h3>
@@ -291,3 +303,221 @@ export function UserDetail() {
     </div>
   );
 }
+
+function UserAssignmentsPanel({ user }: { user: User }) {
+  const qc = useQueryClient();
+  const toast = useToastContext();
+  const { data: clients = [], isLoading: clientsLoading } = useClients();
+  const [selectedClientId, setSelectedClientId] = useState<string | null>(null);
+  const { data: teams = [], isLoading: teamsLoading } = useTeamsForClient(selectedClientId);
+
+  const assignPM = useAssignPMAny();
+  const removePM = useRemovePMAny();
+  const addMember = useAddTeamMemberAny();
+  const removeMember = useRemoveTeamMemberAny();
+
+  const refreshUser = () => qc.invalidateQueries({ queryKey: ['users', user.id] });
+
+  if (clientsLoading) {
+    return (
+      <div className="bg-white shadow rounded-lg p-6">
+        <div className="animate-pulse h-4 bg-gray-200 rounded w-1/2"></div>
+      </div>
+    );
+  }
+
+  if (clients.length === 0) return null;
+
+  if (user.role === 'project_manager') {
+    return (
+      <PMAssignmentsCard
+        user={user}
+        clients={clients}
+        assignPM={assignPM}
+        removePM={removePM}
+        refreshUser={refreshUser}
+        toast={toast}
+      />
+    );
+  }
+
+  return (
+    <TeamMembershipsCard
+      user={user}
+      clients={clients}
+      selectedClientId={selectedClientId}
+      setSelectedClientId={setSelectedClientId}
+      teams={teams}
+      teamsLoading={teamsLoading}
+      addMember={addMember}
+      removeMember={removeMember}
+      toast={toast}
+    />
+  );
+}
+
+function PMAssignmentsCard({
+  user,
+  clients,
+  assignPM,
+  removePM,
+  refreshUser,
+  toast,
+}: {
+  user: User;
+  clients: Client[];
+  assignPM: ReturnType<typeof useAssignPMAny>;
+  removePM: ReturnType<typeof useRemovePMAny>;
+  refreshUser: () => void;
+  toast: ReturnType<typeof useToastContext>;
+}) {
+  const pmClientIds = user.pm_client_ids ?? [];
+
+  const handleToggle = async (clientId: string, isAssigned: boolean) => {
+    try {
+      if (isAssigned) {
+        await removePM.mutateAsync({ clientId, userId: user.id });
+        toast.toastOnly.success('Removed as PM from client');
+      } else {
+        await assignPM.mutateAsync({ clientId, userId: user.id });
+        toast.toastOnly.success('Assigned as PM to client');
+      }
+      refreshUser();
+    } catch {
+      toast.toastOnly.error('Failed to update PM assignment');
+    }
+  };
+
+  const isBusy = assignPM.isPending || removePM.isPending;
+
+  return (
+    <div className="bg-white shadow rounded-lg p-6">
+      <h3 className="text-lg font-medium text-gray-900 mb-4">PM Client Assignments</h3>
+      {clients.length === 0 ? (
+        <p className="text-sm text-gray-500">No clients found.</p>
+      ) : (
+        <ul className="divide-y divide-gray-100">
+          {clients.map((client) => {
+            const isAssigned = pmClientIds.includes(client.id);
+            return (
+              <li key={client.id} className="flex items-center justify-between py-2">
+                <div>
+                  <span className="text-sm font-medium text-gray-900">{client.name}</span>
+                  {!client.is_active && (
+                    <span className="ml-2 text-xs text-gray-400">(inactive)</span>
+                  )}
+                </div>
+                <button
+                  onClick={() => handleToggle(client.id, isAssigned)}
+                  disabled={isBusy}
+                  className={`px-3 py-1 text-xs font-medium rounded-full border transition-colors disabled:opacity-50 ${
+                    isAssigned
+                      ? 'bg-indigo-50 text-indigo-700 border-indigo-200 hover:bg-indigo-100'
+                      : 'bg-gray-50 text-gray-600 border-gray-200 hover:bg-gray-100'
+                  }`}
+                >
+                  {isAssigned ? 'Assigned ✓' : 'Assign'}
+                </button>
+              </li>
+            );
+          })}
+        </ul>
+      )}
+    </div>
+  );
+}
+
+function TeamMembershipsCard({
+  user,
+  clients,
+  selectedClientId,
+  setSelectedClientId,
+  teams,
+  teamsLoading,
+  addMember,
+  removeMember,
+  toast,
+}: {
+  user: User;
+  clients: Client[];
+  selectedClientId: string | null;
+  setSelectedClientId: (id: string | null) => void;
+  teams: Team[];
+  teamsLoading: boolean;
+  addMember: ReturnType<typeof useAddTeamMemberAny>;
+  removeMember: ReturnType<typeof useRemoveTeamMemberAny>;
+  toast: ReturnType<typeof useToastContext>;
+}) {
+  const handleToggle = async (team: Team, isMember: boolean) => {
+    if (!selectedClientId) return;
+    try {
+      if (isMember) {
+        await removeMember.mutateAsync({ clientId: selectedClientId, teamId: team.id, userId: user.id });
+        toast.toastOnly.success(`Removed from team "${team.name}"`);
+      } else {
+        await addMember.mutateAsync({ clientId: selectedClientId, teamId: team.id, userId: user.id });
+        toast.toastOnly.success(`Added to team "${team.name}"`);
+      }
+    } catch {
+      toast.toastOnly.error('Failed to update team membership');
+    }
+  };
+
+  const isBusy = addMember.isPending || removeMember.isPending;
+
+  return (
+    <div className="bg-white shadow rounded-lg p-6">
+      <h3 className="text-lg font-medium text-gray-900 mb-4">Team Memberships</h3>
+      <div className="mb-4">
+        <label className="block text-sm font-medium text-gray-700 mb-1">Select Client</label>
+        <select
+          value={selectedClientId ?? ''}
+          onChange={(e) => setSelectedClientId(e.target.value || null)}
+          className="w-full px-3 py-2 text-sm border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500"
+        >
+          <option value="">— pick a client —</option>
+          {clients.map((c) => (
+            <option key={c.id} value={c.id}>
+              {c.name}
+            </option>
+          ))}
+        </select>
+      </div>
+
+      {selectedClientId && (
+        <>
+          {teamsLoading ? (
+            <div className="animate-pulse space-y-2">
+              <div className="h-4 bg-gray-200 rounded w-3/4"></div>
+              <div className="h-4 bg-gray-200 rounded w-1/2"></div>
+            </div>
+          ) : teams.length === 0 ? (
+            <p className="text-sm text-gray-500">No teams for this client.</p>
+          ) : (
+            <ul className="divide-y divide-gray-100">
+              {teams.map((team) => {
+                const isMember = team.member_user_ids.includes(user.id);
+                return (
+                  <li key={team.id} className="flex items-center justify-between py-2">
+                    <span className="text-sm font-medium text-gray-900">{team.name}</span>
+                    <button
+                      onClick={() => handleToggle(team, isMember)}
+                      disabled={isBusy}
+                      className={`px-3 py-1 text-xs font-medium rounded-full border transition-colors disabled:opacity-50 ${
+                        isMember
+                          ? 'bg-teal-50 text-teal-700 border-teal-200 hover:bg-teal-100'
+                          : 'bg-gray-50 text-gray-600 border-gray-200 hover:bg-gray-100'
+                      }`}
+                    >
+                      {isMember ? 'Member ✓' : 'Add'}
+                    </button>
+                  </li>
+                );
+              })}
+            </ul>
+          )}
+        </>
+      )}
+    </div>
+  );
+}
diff --git a/frontend/src/routes/admin/UserList.tsx b/frontend/src/routes/admin/UserList.tsx
index f4312c6..949d1a6 100644
--- a/frontend/src/routes/admin/UserList.tsx
+++ b/frontend/src/routes/admin/UserList.tsx
@@ -131,6 +131,7 @@ export function UserList() {
             >
               <option value="">All Roles</option>
               <option value="admin">Admin</option>
+              <option value="project_manager">Project Manager</option>
               <option value="production">Production</option>
               <option value="reviewer">Reviewer</option>
               <option value="linguist">Linguist</option>
@@ -216,12 +217,13 @@ export function UserList() {
                     <td className="px-6 py-4 whitespace-nowrap">
                       <span className={`inline-flex items-center px-2.5 py-0.5 rounded-full text-xs font-medium capitalize ${
                         user.role === 'admin' ? 'bg-purple-100 text-purple-800' :
+                        user.role === 'project_manager' ? 'bg-indigo-100 text-indigo-800' :
                         user.role === 'production' ? 'bg-orange-100 text-orange-800' :
                         user.role === 'reviewer' ? 'bg-blue-100 text-blue-800' :
                         user.role === 'linguist' ? 'bg-teal-100 text-teal-800' :
                         'bg-green-100 text-green-800'
                       }`}>
-                        {user.role}
+                        {user.role === 'project_manager' ? 'Project Manager' : user.role}
                       </span>
                     </td>
                     <td className="px-6 py-4 whitespace-nowrap">
@@ -444,6 +446,7 @@ function CreateUserModal({ onClose, onSuccess }: { onClose: () => void; onSucces
               <option value="reviewer">Reviewer</option>
               <option value="linguist">Linguist</option>
               <option value="production">Production</option>
+              <option value="project_manager">Project Manager</option>
               <option value="admin">Admin</option>
             </select>
           </div>
diff --git a/frontend/src/types/api.ts b/frontend/src/types/api.ts
index a132058..7e40455 100644
--- a/frontend/src/types/api.ts
+++ b/frontend/src/types/api.ts
@@ -27,6 +27,7 @@ export interface User {
   auth_provider: AuthProvider;
   is_active: boolean;
   created_at: string;
+  pm_client_ids?: string[];
 }
 
 export interface Source {