diff --git a/.env.example b/.env.example
index 8a108b5..c005b33 100644
--- a/.env.example
+++ b/.env.example
@@ -18,6 +18,9 @@ OIDC_SCOPES=openid profile email
 OIDC_LOGOUT_URL=
 OIDC_ALLOWED_ALGORITHMS=RS256
 OIDC_HTTP_TIMEOUT_MS=5000
+OIDC_ADMIN_ROLE=hauspilot-admin
+OIDC_ROLES_CLAIM=roles
+OIDC_ROLE_MATCH_CASE_SENSITIVE=true
 
 SESSION_COOKIE_NAME=app_session
 SESSION_IDLE_TIMEOUT_SECONDS=28800
diff --git a/README.md b/README.md
index c217d46..40f37c4 100644
--- a/README.md
+++ b/README.md
@@ -61,6 +61,7 @@ laufen.
 - [Architektur](docs/architecture.md): Monorepo, Backend, Frontend, API-Client und Modulgrenzen
 - [Entwicklung](docs/development.md): Workflows fuer Features, Migrationen, Tests und API-Client
 - [Security-Modell](docs/security.md): OIDC, Sessions, CSRF, Rollen, Permissions und Logging
+- [OIDC-Administratoren](docs/oidc-administrator.md): sichere Admin-Synchronisierung und Recovery
 - [Designsystem](docs/design-system.md): Tokens, UI-Komponenten, responsive Regeln und Accessibility
 - [Adminbereich](docs/admin.md): Benutzer, Rollen, Sessions, Audit und letzter-Admin-Schutz
 - [Benachrichtigungen](docs/notifications.md): Datenmodell, API, Permissions, Polling und Erweiterung
diff --git a/apps/backend/src/audit/audit.service.ts b/apps/backend/src/audit/audit.service.ts
index 16060be..b0c4a13 100644
--- a/apps/backend/src/audit/audit.service.ts
+++ b/apps/backend/src/audit/audit.service.ts
@@ -2,6 +2,7 @@ import { Injectable } from '@nestjs/common';
 import { getRequestId } from '../common/request-context/request-context';
 import { AuditAction, AuditLogEntity } from './entities/audit-log.entity';
 import { AuditRepository } from './repositories/audit.repository';
+import type { EntityManager } from 'typeorm';
 
 @Injectable()
 export class AuditService {
@@ -13,6 +14,7 @@ export class AuditService {
     targetType: string,
     targetId: string,
     metadata: Record<string, string | number | boolean | null> | null = null,
+    manager?: EntityManager,
   ): Promise<void> {
     const entry = new AuditLogEntity();
     entry.actorUserId = actorUserId;
@@ -21,7 +23,7 @@ export class AuditService {
     entry.targetId = targetId;
     entry.metadata = metadata;
     entry.requestId = getRequestId();
-    await this.audit.save(entry);
+    await this.audit.save(entry, manager);
   }
 
   async list(page = 1, pageSize = 20) {
diff --git a/apps/backend/src/audit/entities/audit-log.entity.ts b/apps/backend/src/audit/entities/audit-log.entity.ts
index ce09ec0..592abee 100644
--- a/apps/backend/src/audit/entities/audit-log.entity.ts
+++ b/apps/backend/src/audit/entities/audit-log.entity.ts
@@ -11,6 +11,8 @@ export enum AuditAction {
   UserDeactivated = 'USER_DEACTIVATED',
   UserRoleAssigned = 'USER_ROLE_ASSIGNED',
   UserRoleRemoved = 'USER_ROLE_REMOVED',
+  OidcAdminAssigned = 'OIDC_ADMIN_ASSIGNED',
+  OidcAdminRemoved = 'OIDC_ADMIN_REMOVED',
   RoleCreated = 'ROLE_CREATED',
   RoleUpdated = 'ROLE_UPDATED',
   RoleDeleted = 'ROLE_DELETED',
diff --git a/apps/backend/src/audit/repositories/audit.repository.ts b/apps/backend/src/audit/repositories/audit.repository.ts
index ed41615..0aaf7cb 100644
--- a/apps/backend/src/audit/repositories/audit.repository.ts
+++ b/apps/backend/src/audit/repositories/audit.repository.ts
@@ -1,6 +1,6 @@
 import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import { Repository } from 'typeorm';
+import { EntityManager, Repository } from 'typeorm';
 import { AuditLogEntity } from '../entities/audit-log.entity';
 
 @Injectable()
@@ -10,8 +10,11 @@ export class AuditRepository {
     private readonly repo: Repository<AuditLogEntity>,
   ) {}
 
-  save(entry: AuditLogEntity): Promise<AuditLogEntity> {
-    return this.repo.save(entry);
+  save(
+    entry: AuditLogEntity,
+    manager?: EntityManager,
+  ): Promise<AuditLogEntity> {
+    return (manager?.getRepository(AuditLogEntity) ?? this.repo).save(entry);
   }
 
   list(page: number, pageSize: number): Promise<[AuditLogEntity[], number]> {
diff --git a/apps/backend/src/auth/auth.module.ts b/apps/backend/src/auth/auth.module.ts
index 86393cf..955089d 100644
--- a/apps/backend/src/auth/auth.module.ts
+++ b/apps/backend/src/auth/auth.module.ts
@@ -9,6 +9,10 @@ import { UsersRepository } from '../users/repositories/users.repository';
 import { OidcLoginStateEntity } from './entities/oidc-login-state.entity';
 import { AuthController } from './auth.controller';
 import { AuthService } from './auth.service';
+import { OidcRoleExtractorService } from './oidc-role-extractor.service';
+import { OidcAdminSynchronizationService } from './oidc-admin-synchronization.service';
+import { UserRoleAssignmentEntity } from '../users/entities/user-role-assignment.entity';
+import { AuditModule } from '../audit/audit.module';
 
 @Module({
   imports: [
@@ -16,12 +20,20 @@ import { AuthService } from './auth.service';
       OidcLoginStateEntity,
       UserEntity,
       UserSettingsEntity,
+      UserRoleAssignmentEntity,
     ]),
     RolesModule,
     SessionsModule,
+    AuditModule,
   ],
   controllers: [AuthController],
-  providers: [AuthService, ExternalHttpClient, UsersRepository],
+  providers: [
+    AuthService,
+    ExternalHttpClient,
+    UsersRepository,
+    OidcRoleExtractorService,
+    OidcAdminSynchronizationService,
+  ],
   exports: [AuthService],
 })
 export class AuthModule {}
diff --git a/apps/backend/src/auth/auth.service.spec.ts b/apps/backend/src/auth/auth.service.spec.ts
index 131e97a..cab0b9b 100644
--- a/apps/backend/src/auth/auth.service.spec.ts
+++ b/apps/backend/src/auth/auth.service.spec.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it, vi } from 'vitest';
-import type { DataSource, Repository } from 'typeorm';
+import type { DataSource, EntityManager, Repository } from 'typeorm';
 import type { ExternalHttpClient } from '../common/http/external-http-client';
 import type { AppConfigService } from '../config/config.service';
 import type { RolesService } from '../roles/roles.service';
@@ -7,8 +7,82 @@ import type { SessionsService } from '../sessions/sessions.service';
 import type { UsersRepository } from '../users/repositories/users.repository';
 import type { OidcLoginStateEntity } from './entities/oidc-login-state.entity';
 import { AuthService } from './auth.service';
+import type { OidcAdminSynchronizationService } from './oidc-admin-synchronization.service';
+import { UserEntity } from '../users/entities/user.entity';
+import { UserSettingsEntity } from '../users/entities/user-settings.entity';
+import type { RoleEntity } from '../roles/entities/role.entity';
 
 describe('AuthService', () => {
+  it('does not grant the first or second provisioned user the admin role', async () => {
+    let sequence = 0;
+    const userRole = {
+      id: 'role-user',
+      name: 'user',
+      roleKey: 'USER',
+    } as RoleEntity;
+    const adminRole = {
+      id: 'role-admin',
+      name: 'admin',
+      roleKey: 'ADMIN',
+    } as RoleEntity;
+    const manager = {
+      query: () => Promise.resolve(),
+      getRepository: (entity: unknown) => {
+        if (entity === UserEntity) {
+          return {
+            findOne: () => Promise.resolve(null),
+            save: (user: UserEntity) => {
+              user.id = `user-${++sequence}`;
+              return Promise.resolve(user);
+            },
+          };
+        }
+        if (entity === UserSettingsEntity) {
+          return {
+            findOne: () => Promise.resolve(null),
+            save: (settings: UserSettingsEntity) => Promise.resolve(settings),
+          };
+        }
+        throw new Error('Unerwartetes Repository');
+      },
+    } as unknown as EntityManager;
+    const service = new AuthService(
+      {} as AppConfigService,
+      {} as ExternalHttpClient,
+      {
+        ensureSystemRoles: () =>
+          Promise.resolve({ admin: adminRole, user: userRole }),
+      } as unknown as RolesService,
+      {} as UsersRepository,
+      {} as SessionsService,
+      {} as OidcAdminSynchronizationService,
+      {
+        transaction: <T>(
+          action: (transactionManager: EntityManager) => Promise<T>,
+        ) => action(manager),
+      } as DataSource,
+      {} as Repository<OidcLoginStateEntity>,
+    );
+    const provision = service as unknown as {
+      upsertLocalUser: (
+        issuer: string,
+        profile: { sub: string; name: string },
+      ) => Promise<UserEntity>;
+    };
+
+    const first = await provision.upsertLocalUser('issuer', {
+      sub: 'first',
+      name: 'First',
+    });
+    const second = await provision.upsertLocalUser('issuer', {
+      sub: 'second',
+      name: 'Second',
+    });
+
+    expect(first.roles.map((role) => role.roleKey)).toEqual(['USER']);
+    expect(second.roles.map((role) => role.roleKey)).toEqual(['USER']);
+  });
+
   it('stores only an internal return path in the short-lived OIDC login state', async () => {
     const saved: OidcLoginStateEntity[] = [];
     const service = new AuthService(
@@ -36,6 +110,7 @@ describe('AuthService', () => {
       {} as RolesService,
       {} as UsersRepository,
       {} as SessionsService,
+      {} as OidcAdminSynchronizationService,
       {} as DataSource,
       {
         delete: () => Promise.resolve({}),
@@ -76,6 +151,7 @@ describe('AuthService', () => {
       {} as RolesService,
       {} as UsersRepository,
       { revoke, getIdTokenForLogout } as unknown as SessionsService,
+      {} as OidcAdminSynchronizationService,
       {} as DataSource,
       {} as Repository<OidcLoginStateEntity>,
     );
diff --git a/apps/backend/src/auth/auth.service.ts b/apps/backend/src/auth/auth.service.ts
index 64d3d93..3bc0bc4 100644
--- a/apps/backend/src/auth/auth.service.ts
+++ b/apps/backend/src/auth/auth.service.ts
@@ -17,6 +17,8 @@ import type {
   OidcTokenResponse,
   OidcUserInfo,
 } from './oidc.types';
+import { OidcAdminSynchronizationService } from './oidc-admin-synchronization.service';
+import { UserRoleAssignmentSource } from '../users/entities/user-role-assignment.entity';
 
 @Injectable()
 export class AuthService {
@@ -26,6 +28,7 @@ export class AuthService {
     private readonly roles: RolesService,
     private readonly users: UsersRepository,
     private readonly sessions: SessionsService,
+    private readonly adminSynchronization: OidcAdminSynchronizationService,
     @InjectDataSource() private readonly dataSource: DataSource,
     @InjectRepository(OidcLoginStateEntity)
     private readonly loginStates: Repository<OidcLoginStateEntity>,
@@ -83,12 +86,12 @@ export class AuthService {
       code,
       loginState.codeVerifier,
     );
-    const profile = await this.verifyAndLoadProfile(
+    const { profile, claims } = await this.verifyAndLoadProfile(
       discovery,
       tokens,
       loginState.nonce,
     );
-    const user = await this.upsertLocalUser(discovery.issuer, profile);
+    let user = await this.upsertLocalUser(discovery.issuer, profile);
     if (!user.active) {
       throw new ApiError(
         ErrorCode.UserDisabled,
@@ -96,6 +99,7 @@ export class AuthService {
         403,
       );
     }
+    user = await this.adminSynchronization.synchronize(user.id, claims);
 
     const result = await this.sessions.createSession(
       user,
@@ -129,8 +133,7 @@ export class AuthService {
     return this.dataSource.transaction(async (manager) => {
       await manager.query("SELECT GET_LOCK('business_app_first_admin', 10)");
       try {
-        const { admin, user: userRole } =
-          await this.roles.ensureSystemRoles(manager);
+        const { user: userRole } = await this.roles.ensureSystemRoles(manager);
         let user = await manager.getRepository(UserEntity).findOne({
           where: { issuer, subject: profile.sub },
           relations: { roles: true, settings: true },
@@ -141,10 +144,6 @@ export class AuthService {
           user.subject = profile.sub;
           user.active = true;
           user.roles = [userRole];
-          const userCount = await manager.getRepository(UserEntity).count();
-          if (userCount === 0) {
-            user.roles = [userRole, admin];
-          }
         }
         user.name = profile.name ?? profile.email ?? profile.sub;
         user.email = profile.email ?? null;
@@ -154,6 +153,12 @@ export class AuthService {
             : null;
         user.lastLoginAt = new Date();
         const savedUser = await manager.getRepository(UserEntity).save(user);
+        await manager.query(
+          `INSERT IGNORE INTO user_role_assignments
+             (id, user_id, role_id, source, last_synchronized_at, created_at, updated_at)
+           VALUES (UUID(), ?, ?, ?, NULL, CURRENT_TIMESTAMP(3), CURRENT_TIMESTAMP(3))`,
+          [savedUser.id, userRole.id, UserRoleAssignmentSource.System],
+        );
         savedUser.settings = await this.ensureUserSettings(manager, savedUser);
         return savedUser;
       } finally {
@@ -266,7 +271,7 @@ export class AuthService {
     discovery: OidcDiscovery,
     tokens: OidcTokenResponse,
     nonce: string,
-  ): Promise<OidcUserInfo> {
+  ): Promise<{ profile: OidcUserInfo; claims: Record<string, unknown> }> {
     const { createRemoteJWKSet, decodeProtectedHeader, jwtVerify } =
       await import('jose');
     const protectedHeader = decodeProtectedHeader(tokens.id_token);
@@ -305,7 +310,7 @@ export class AuthService {
       if (typeof payload['email_verified'] === 'boolean') {
         fallback.email_verified = payload['email_verified'];
       }
-      return fallback;
+      return { profile: fallback, claims: { ...payload } };
     }
     const userInfo = await this.http.requestJson<OidcUserInfo>(
       discovery.userinfo_endpoint,
@@ -335,7 +340,7 @@ export class AuthService {
     ) {
       userInfo.email_verified = payload['email_verified'];
     }
-    return userInfo;
+    return { profile: userInfo, claims: { ...payload, ...userInfo } };
   }
 
   private isAllowedOidcAlgorithm(algorithm: string | undefined): boolean {
diff --git a/apps/backend/src/auth/oidc-admin-synchronization.service.spec.ts b/apps/backend/src/auth/oidc-admin-synchronization.service.spec.ts
new file mode 100644
index 0000000..9535793
--- /dev/null
+++ b/apps/backend/src/auth/oidc-admin-synchronization.service.spec.ts
@@ -0,0 +1,140 @@
+import { describe, expect, it, vi } from 'vitest';
+import type { DataSource, EntityManager } from 'typeorm';
+import type { AuditService } from '../audit/audit.service';
+import type { AppConfigService } from '../config/config.service';
+import type { RoleEntity } from '../roles/entities/role.entity';
+import type { RolesService } from '../roles/roles.service';
+import type { UserEntity } from '../users/entities/user.entity';
+import { UserRoleAssignmentSource } from '../users/entities/user-role-assignment.entity';
+import { OidcAdminSynchronizationService } from './oidc-admin-synchronization.service';
+import { OidcRoleExtractorService } from './oidc-role-extractor.service';
+
+function fixture(
+  existing: boolean,
+  remainingSources = 0,
+  adminRole: string | undefined = 'hauspilot-admin',
+  caseSensitive = true,
+) {
+  const assignment = {
+    id: 'assignment-1',
+    userId: 'user-1',
+    roleId: 'admin-role',
+    source: UserRoleAssignmentSource.Oidc,
+    lastSynchronizedAt: new Date(),
+  };
+  const repository = {
+    findOneBy: vi.fn(() => Promise.resolve(existing ? assignment : null)),
+    save: vi.fn(() => Promise.resolve(assignment)),
+    insert: vi.fn(() =>
+      Promise.resolve({ identifiers: [], generatedMaps: [], raw: [] }),
+    ),
+    remove: vi.fn(() => Promise.resolve(assignment)),
+    countBy: vi.fn(() => Promise.resolve(remainingSources)),
+  };
+  const query = vi.fn(() => Promise.resolve([]));
+  const manager = {
+    getRepository: () => repository,
+    query,
+  } as unknown as EntityManager;
+  const user = { id: 'user-1', roles: [] } as unknown as UserEntity;
+  const dataSource = {
+    transaction: (callback: (value: EntityManager) => Promise<void>) =>
+      callback(manager),
+    getRepository: () => ({ findOne: () => Promise.resolve(user) }),
+  } as unknown as DataSource;
+  const audit = {
+    record: vi.fn(() => Promise.resolve()),
+  } as unknown as AuditService;
+  const roles = {
+    ensureSystemRoles: () =>
+      Promise.resolve({
+        admin: { id: 'admin-role' } as RoleEntity,
+        user: {} as RoleEntity,
+      }),
+  } as RolesService;
+  const config = {
+    oidc: {
+      adminRole,
+      rolesClaim: 'realm_access.roles',
+      roleMatchCaseSensitive: caseSensitive,
+    },
+  } as AppConfigService;
+  return {
+    service: new OidcAdminSynchronizationService(
+      config,
+      new OidcRoleExtractorService(),
+      roles,
+      audit,
+      dataSource,
+    ),
+    repository,
+    query,
+    audit,
+  };
+}
+
+describe('OidcAdminSynchronizationService', () => {
+  it('adds the OIDC source and effective admin role idempotently', async () => {
+    const first = fixture(false);
+    await first.service.synchronize('user-1', {
+      realm_access: { roles: ['hauspilot-admin'] },
+    });
+    expect(first.query).toHaveBeenCalledWith(
+      expect.stringContaining('ON DUPLICATE KEY UPDATE'),
+      ['user-1', 'admin-role', UserRoleAssignmentSource.Oidc],
+    );
+    expect(first.query).toHaveBeenCalledWith(
+      'INSERT IGNORE INTO user_roles (user_id, role_id) VALUES (?, ?)',
+      ['user-1', 'admin-role'],
+    );
+
+    const repeated = fixture(true);
+    await repeated.service.synchronize('user-1', {
+      realm_access: { roles: ['hauspilot-admin'] },
+    });
+    expect(repeated.repository.save).toHaveBeenCalledOnce();
+  });
+
+  it('removes only the OIDC source while another source keeps the effective role', async () => {
+    const current = fixture(true, 1);
+    await current.service.synchronize('user-1', {
+      realm_access: { roles: ['hauspilot-user'] },
+    });
+    expect(current.repository.remove).toHaveBeenCalledOnce();
+    expect(current.query).not.toHaveBeenCalledWith(
+      'DELETE FROM user_roles WHERE user_id = ? AND role_id = ?',
+      expect.anything(),
+    );
+  });
+
+  it('fails safely without changing assignments when the configured claim is missing', async () => {
+    const current = fixture(true);
+    await expect(
+      current.service.synchronize('user-1', { sub: '123' }),
+    ).rejects.toMatchObject({
+      status: 401,
+    });
+    expect(current.repository.remove).not.toHaveBeenCalled();
+    expect(current.repository.insert).not.toHaveBeenCalled();
+  });
+
+  it('does not add or remove assignments when synchronization is disabled', async () => {
+    const current = fixture(true, 0, '');
+    await current.service.synchronize('user-1', {
+      realm_access: { roles: [] },
+    });
+    expect(current.repository.remove).not.toHaveBeenCalled();
+    expect(current.query).not.toHaveBeenCalled();
+  });
+
+  it('honors case-insensitive matching only when explicitly configured', async () => {
+    const current = fixture(false, 0, 'hauspilot-admin', false);
+    await current.service.synchronize('user-1', {
+      realm_access: { roles: ['HAUSPILOT-ADMIN'] },
+    });
+    expect(current.query).toHaveBeenCalledWith(
+      expect.stringContaining('ON DUPLICATE KEY UPDATE'),
+      ['user-1', 'admin-role', UserRoleAssignmentSource.Oidc],
+    );
+  });
+});
diff --git a/apps/backend/src/auth/oidc-admin-synchronization.service.ts b/apps/backend/src/auth/oidc-admin-synchronization.service.ts
new file mode 100644
index 0000000..9b7fe4f
--- /dev/null
+++ b/apps/backend/src/auth/oidc-admin-synchronization.service.ts
@@ -0,0 +1,139 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { InjectDataSource } from '@nestjs/typeorm';
+import { DataSource } from 'typeorm';
+import { AuditService } from '../audit/audit.service';
+import { AuditAction } from '../audit/entities/audit-log.entity';
+import { ApiError } from '../common/errors/api-error';
+import { ErrorCode } from '../common/errors/error-codes';
+import { AppConfigService } from '../config/config.service';
+import { RolesService } from '../roles/roles.service';
+import { UserEntity } from '../users/entities/user.entity';
+import {
+  UserRoleAssignmentEntity,
+  UserRoleAssignmentSource,
+} from '../users/entities/user-role-assignment.entity';
+import { OidcRoleExtractorService } from './oidc-role-extractor.service';
+
+@Injectable()
+export class OidcAdminSynchronizationService {
+  private readonly logger = new Logger(OidcAdminSynchronizationService.name);
+
+  constructor(
+    private readonly config: AppConfigService,
+    private readonly extractor: OidcRoleExtractorService,
+    private readonly roles: RolesService,
+    private readonly audit: AuditService,
+    @InjectDataSource() private readonly dataSource: DataSource,
+  ) {}
+
+  async synchronize(
+    userId: string,
+    claims: Readonly<Record<string, unknown>>,
+  ): Promise<UserEntity> {
+    const adminRoleName = this.config.oidc.adminRole;
+    if (!adminRoleName) return this.reloadUser(userId);
+    const claimPath = this.config.oidc.rolesClaim;
+    if (!claimPath)
+      throw new Error(
+        'OIDC_ROLES_CLAIM fehlt trotz validierter Konfiguration.',
+      );
+    const extracted = this.extractor.extract(claims, claimPath);
+    if (!extracted.readable) {
+      this.logger.error(
+        { userId, claimPath, reason: extracted.reason },
+        'OIDC-Administrator-Synchronisierung: Rollenclaim konnte nicht gelesen werden',
+      );
+      throw new ApiError(
+        ErrorCode.Unauthorized,
+        'Die OIDC-Rollen konnten nicht sicher validiert werden.',
+        401,
+      );
+    }
+    const normalize = (value: string) =>
+      this.config.oidc.roleMatchCaseSensitive
+        ? value
+        : value.toLocaleLowerCase('en-US');
+    const hasAdminRole = extracted.roles.some(
+      (role) => normalize(role) === normalize(adminRoleName),
+    );
+
+    await this.dataSource.transaction(async (manager) => {
+      const { admin } = await this.roles.ensureSystemRoles(manager);
+      const assignments = manager.getRepository(UserRoleAssignmentEntity);
+      const existing = await assignments.findOneBy({
+        userId,
+        roleId: admin.id,
+        source: UserRoleAssignmentSource.Oidc,
+      });
+      if (hasAdminRole) {
+        if (existing) {
+          existing.lastSynchronizedAt = new Date();
+          await assignments.save(existing);
+        } else {
+          await manager.query(
+            `INSERT INTO user_role_assignments
+               (id, user_id, role_id, source, last_synchronized_at, created_at, updated_at)
+             VALUES (UUID(), ?, ?, ?, CURRENT_TIMESTAMP(3), CURRENT_TIMESTAMP(3), CURRENT_TIMESTAMP(3))
+             ON DUPLICATE KEY UPDATE last_synchronized_at = CURRENT_TIMESTAMP(3), updated_at = CURRENT_TIMESTAMP(3)`,
+            [userId, admin.id, UserRoleAssignmentSource.Oidc],
+          );
+          await manager.query(
+            'INSERT IGNORE INTO user_roles (user_id, role_id) VALUES (?, ?)',
+            [userId, admin.id],
+          );
+          await this.audit.record(
+            userId,
+            AuditAction.OidcAdminAssigned,
+            'user',
+            userId,
+            {
+              roleId: admin.id,
+              oidcRole: adminRoleName,
+              source: UserRoleAssignmentSource.Oidc,
+            },
+            manager,
+          );
+        }
+      } else if (existing) {
+        await assignments.remove(existing);
+        const remaining = await assignments.countBy({
+          userId,
+          roleId: admin.id,
+        });
+        if (remaining === 0) {
+          await manager.query(
+            'DELETE FROM user_roles WHERE user_id = ? AND role_id = ?',
+            [userId, admin.id],
+          );
+        }
+        await this.audit.record(
+          userId,
+          AuditAction.OidcAdminRemoved,
+          'user',
+          userId,
+          {
+            roleId: admin.id,
+            oidcRole: adminRoleName,
+            source: UserRoleAssignmentSource.Oidc,
+          },
+          manager,
+        );
+      }
+    });
+    return this.reloadUser(userId);
+  }
+
+  private async reloadUser(userId: string): Promise<UserEntity> {
+    const user = await this.dataSource.getRepository(UserEntity).findOne({
+      where: { id: userId },
+      relations: { roles: { permissions: true }, settings: true },
+    });
+    if (!user)
+      throw new ApiError(
+        ErrorCode.UserNotFound,
+        'Der Benutzer wurde nicht gefunden.',
+        404,
+      );
+    return user;
+  }
+}
diff --git a/apps/backend/src/auth/oidc-role-extractor.service.spec.ts b/apps/backend/src/auth/oidc-role-extractor.service.spec.ts
new file mode 100644
index 0000000..fbb1704
--- /dev/null
+++ b/apps/backend/src/auth/oidc-role-extractor.service.spec.ts
@@ -0,0 +1,49 @@
+import { describe, expect, it } from 'vitest';
+import { OidcRoleExtractorService } from './oidc-role-extractor.service';
+
+describe('OidcRoleExtractorService', () => {
+  const extractor = new OidcRoleExtractorService();
+
+  it('reads nested arrays, trims values and removes duplicates and empty roles', () => {
+    expect(
+      extractor.extract(
+        {
+          realm_access: {
+            roles: [
+              ' hauspilot-admin ',
+              'hauspilot-user',
+              '',
+              'hauspilot-admin',
+            ],
+          },
+        },
+        'realm_access.roles',
+      ),
+    ).toEqual({ readable: true, roles: ['hauspilot-admin', 'hauspilot-user'] });
+  });
+
+  it('accepts a single role string', () => {
+    expect(extractor.extract({ roles: 'hauspilot-admin' }, 'roles')).toEqual({
+      readable: true,
+      roles: ['hauspilot-admin'],
+    });
+  });
+
+  it('distinguishes a missing claim from a valid claim without the admin role', () => {
+    expect(extractor.extract({ sub: '123' }, 'roles')).toEqual({
+      readable: false,
+      reason: 'missing',
+    });
+    expect(extractor.extract({ roles: ['hauspilot-user'] }, 'roles')).toEqual({
+      readable: true,
+      roles: ['hauspilot-user'],
+    });
+  });
+
+  it('rejects mixed or object claim formats', () => {
+    expect(extractor.extract({ roles: ['valid', 42] }, 'roles')).toEqual({
+      readable: false,
+      reason: 'invalid',
+    });
+  });
+});
diff --git a/apps/backend/src/auth/oidc-role-extractor.service.ts b/apps/backend/src/auth/oidc-role-extractor.service.ts
new file mode 100644
index 0000000..a53f655
--- /dev/null
+++ b/apps/backend/src/auth/oidc-role-extractor.service.ts
@@ -0,0 +1,44 @@
+import { Injectable } from '@nestjs/common';
+
+export type OidcRoleExtractionResult =
+  | { readable: true; roles: string[] }
+  | { readable: false; reason: 'missing' | 'invalid' };
+
+@Injectable()
+export class OidcRoleExtractorService {
+  extract(
+    claims: Readonly<Record<string, unknown>>,
+    claimPath: string,
+  ): OidcRoleExtractionResult {
+    let value: unknown = claims;
+    for (const segment of claimPath.split('.')) {
+      if (
+        typeof value !== 'object' ||
+        value === null ||
+        Array.isArray(value) ||
+        !(segment in value)
+      ) {
+        return { readable: false, reason: 'missing' };
+      }
+      value = (value as Record<string, unknown>)[segment];
+    }
+    const values: unknown[] =
+      typeof value === 'string' ? [value] : Array.isArray(value) ? value : [];
+    if (
+      (!Array.isArray(value) && typeof value !== 'string') ||
+      values.some((entry) => typeof entry !== 'string')
+    ) {
+      return { readable: false, reason: 'invalid' };
+    }
+    const roles: string[] = [];
+    for (const entry of values) {
+      if (typeof entry !== 'string') continue;
+      const role = entry.trim();
+      if (role && !roles.includes(role)) roles.push(role);
+    }
+    return {
+      readable: true,
+      roles,
+    };
+  }
+}
diff --git a/apps/backend/src/config/config.service.spec.ts b/apps/backend/src/config/config.service.spec.ts
index e36faac..6372954 100644
--- a/apps/backend/src/config/config.service.spec.ts
+++ b/apps/backend/src/config/config.service.spec.ts
@@ -101,4 +101,30 @@ describe('loadConfigFromEnv', () => {
       }),
     ).toThrow(/OIDC_ALLOWED_ALGORITHMS/);
   });
+
+  it('reads and trims the OIDC administrator mapping without an unsafe default', () => {
+    const configured = loadConfigFromEnv({
+      ...validEnv,
+      OIDC_ADMIN_ROLE: '  hauspilot-admin  ',
+      OIDC_ROLES_CLAIM: 'realm_access.roles',
+    });
+    const disabled = loadConfigFromEnv({ ...validEnv, OIDC_ADMIN_ROLE: '' });
+
+    expect(configured.oidc.adminRole).toBe('hauspilot-admin');
+    expect(configured.oidc.rolesClaim).toBe('realm_access.roles');
+    expect(disabled.oidc.adminRole).toBeUndefined();
+  });
+
+  it('requires a valid roles claim path when OIDC admin synchronization is enabled', () => {
+    expect(() =>
+      loadConfigFromEnv({ ...validEnv, OIDC_ADMIN_ROLE: 'hauspilot-admin' }),
+    ).toThrow(/OIDC_ROLES_CLAIM/);
+    expect(() =>
+      loadConfigFromEnv({
+        ...validEnv,
+        OIDC_ADMIN_ROLE: 'hauspilot-admin',
+        OIDC_ROLES_CLAIM: 'realm access.roles',
+      }),
+    ).toThrow(/OIDC_ROLES_CLAIM/);
+  });
 });
diff --git a/apps/backend/src/config/config.types.ts b/apps/backend/src/config/config.types.ts
index c02e04d..6342862 100644
--- a/apps/backend/src/config/config.types.ts
+++ b/apps/backend/src/config/config.types.ts
@@ -26,6 +26,9 @@ export interface AppConfig {
     scopes: string;
     allowedAlgorithms: string[];
     httpTimeoutMs: number;
+    adminRole?: string;
+    rolesClaim?: string;
+    roleMatchCaseSensitive: boolean;
     logoutUrl?: string;
   };
   session: {
diff --git a/apps/backend/src/config/env.ts b/apps/backend/src/config/env.ts
index 2ecb915..0635e89 100644
--- a/apps/backend/src/config/env.ts
+++ b/apps/backend/src/config/env.ts
@@ -10,85 +10,129 @@ const booleanFromString = z
   .pipe(z.enum(['true', 'false']))
   .transform((value) => value === 'true');
 
-const envSchema = z.object({
-  NODE_ENV: z
-    .enum(['development', 'test', 'production'])
-    .default('development'),
-  PORT: z.coerce.number().int().min(1).max(65535).default(3000),
-  APP_BASE_URL: z.url(),
-  FRONTEND_BASE_URL: z.url().optional(),
-  TRUST_PROXY: booleanFromString.default(false),
-  DATABASE_HOST: z.string().min(1),
-  DATABASE_PORT: z.coerce.number().int().min(1).max(65535).default(3306),
-  DATABASE_NAME: z.string().min(1),
-  DATABASE_USER: z.string().min(1),
-  DATABASE_PASSWORD: z.string().min(1),
-  DATABASE_SSL: booleanFromString.default(false),
-  OIDC_ISSUER: z.url(),
-  OIDC_CLIENT_ID: z.string().min(1),
-  OIDC_CLIENT_SECRET: z.string().min(1),
-  OIDC_SCOPES: z.string().min(1).default('openid profile email'),
-  OIDC_LOGOUT_URL: z.preprocess(
-    (value) => (value === '' ? undefined : value),
-    z.url().optional(),
-  ),
-  OIDC_ALLOWED_ALGORITHMS: z
-    .string()
-    .min(1)
-    .transform((value) =>
+const optionalTrimmedString = (maxLength: number) =>
+  z.preprocess(
+    (value) =>
+      typeof value === 'string' && value.trim() === '' ? undefined : value,
+    z
+      .string()
+      .trim()
+      .max(maxLength)
+      .refine((value) =>
+        Array.from(value).every((character) => {
+          const code = character.charCodeAt(0);
+          return code > 31 && code !== 127;
+        }),
+      )
+      .optional(),
+  );
+
+const envSchema = z
+  .object({
+    NODE_ENV: z
+      .enum(['development', 'test', 'production'])
+      .default('development'),
+    PORT: z.coerce.number().int().min(1).max(65535).default(3000),
+    APP_BASE_URL: z.url(),
+    FRONTEND_BASE_URL: z.url().optional(),
+    TRUST_PROXY: booleanFromString.default(false),
+    DATABASE_HOST: z.string().min(1),
+    DATABASE_PORT: z.coerce.number().int().min(1).max(65535).default(3306),
+    DATABASE_NAME: z.string().min(1),
+    DATABASE_USER: z.string().min(1),
+    DATABASE_PASSWORD: z.string().min(1),
+    DATABASE_SSL: booleanFromString.default(false),
+    OIDC_ISSUER: z.url(),
+    OIDC_CLIENT_ID: z.string().min(1),
+    OIDC_CLIENT_SECRET: z.string().min(1),
+    OIDC_SCOPES: z.string().min(1).default('openid profile email'),
+    OIDC_LOGOUT_URL: z.preprocess(
+      (value) => (value === '' ? undefined : value),
+      z.url().optional(),
+    ),
+    OIDC_ALLOWED_ALGORITHMS: z
+      .string()
+      .min(1)
+      .transform((value) =>
+        value
+          .split(/[\s,]+/)
+          .map((entry) => entry.trim())
+          .filter(Boolean),
+      )
+      .refine(
+        (algorithms) =>
+          algorithms.length > 0 &&
+          algorithms.every((algorithm) => algorithm.toLowerCase() !== 'none'),
+        'OIDC_ALLOWED_ALGORITHMS darf none nicht erlauben.',
+      ),
+    OIDC_HTTP_TIMEOUT_MS: z.coerce
+      .number()
+      .int()
+      .min(1000)
+      .max(30000)
+      .default(5000),
+    OIDC_ADMIN_ROLE: optionalTrimmedString(160),
+    OIDC_ROLES_CLAIM: optionalTrimmedString(255).refine(
+      (value) =>
+        value === undefined ||
+        /^[A-Za-z0-9_-]+(?:\.[A-Za-z0-9_-]+)*$/.test(value),
+      'OIDC_ROLES_CLAIM muss ein gueltiger Claim-Pfad sein.',
+    ),
+    OIDC_ROLE_MATCH_CASE_SENSITIVE: booleanFromString.default(true),
+    SESSION_COOKIE_NAME: z.string().min(1).default('app_session'),
+    SESSION_IDLE_TIMEOUT_SECONDS: z.coerce
+      .number()
+      .int()
+      .min(300)
+      .default(28800),
+    SESSION_ABSOLUTE_TIMEOUT_SECONDS: z.coerce
+      .number()
+      .int()
+      .min(3600)
+      .default(604800),
+    SESSION_SECRET: z.string().min(32),
+    SESSION_ENCRYPTION_KEY: z.string().min(32),
+    CORS_ORIGINS: z.string().transform((value) =>
       value
-        .split(/[\s,]+/)
+        .split(',')
         .map((entry) => entry.trim())
         .filter(Boolean),
-    )
-    .refine(
-      (algorithms) =>
-        algorithms.length > 0 &&
-        algorithms.every((algorithm) => algorithm.toLowerCase() !== 'none'),
-      'OIDC_ALLOWED_ALGORITHMS darf none nicht erlauben.',
     ),
-  OIDC_HTTP_TIMEOUT_MS: z.coerce
-    .number()
-    .int()
-    .min(1000)
-    .max(30000)
-    .default(5000),
-  SESSION_COOKIE_NAME: z.string().min(1).default('app_session'),
-  SESSION_IDLE_TIMEOUT_SECONDS: z.coerce.number().int().min(300).default(28800),
-  SESSION_ABSOLUTE_TIMEOUT_SECONDS: z.coerce
-    .number()
-    .int()
-    .min(3600)
-    .default(604800),
-  SESSION_SECRET: z.string().min(32),
-  SESSION_ENCRYPTION_KEY: z.string().min(32),
-  CORS_ORIGINS: z.string().transform((value) =>
-    value
-      .split(',')
-      .map((entry) => entry.trim())
-      .filter(Boolean),
-  ),
-  CSRF_HEADER_NAME: z.string().min(1).default('X-CSRF-Token'),
-  LOG_LEVEL: z.string().min(1).default('info'),
-  SWAGGER_ENABLED: booleanFromString.default(false),
-  DOCUMENT_STORAGE_PATH: z.string().min(1).default('storage/documents'),
-  DOCUMENT_MAX_FILE_SIZE_BYTES: z.coerce
-    .number()
-    .int()
-    .min(1024)
-    .max(50 * 1024 * 1024)
-    .default(10 * 1024 * 1024),
-  REMINDER_INTERVAL_MS: z.coerce.number().int().min(60000).default(900000),
-  REMINDER_DUE_SOON_DAYS: z.coerce.number().int().min(1).max(30).default(3),
-  RATE_LIMIT_WINDOW_SECONDS: z.coerce.number().int().min(1).default(60),
-  RATE_LIMIT_MAX_REQUESTS: z.coerce.number().int().min(1).default(300),
-  RATE_LIMIT_SENSITIVE_WINDOW_SECONDS: z.coerce
-    .number()
-    .int()
-    .min(1)
-    .default(60),
-  RATE_LIMIT_SENSITIVE_MAX_REQUESTS: z.coerce.number().int().min(1).default(10),
-});
+    CSRF_HEADER_NAME: z.string().min(1).default('X-CSRF-Token'),
+    LOG_LEVEL: z.string().min(1).default('info'),
+    SWAGGER_ENABLED: booleanFromString.default(false),
+    DOCUMENT_STORAGE_PATH: z.string().min(1).default('storage/documents'),
+    DOCUMENT_MAX_FILE_SIZE_BYTES: z.coerce
+      .number()
+      .int()
+      .min(1024)
+      .max(50 * 1024 * 1024)
+      .default(10 * 1024 * 1024),
+    REMINDER_INTERVAL_MS: z.coerce.number().int().min(60000).default(900000),
+    REMINDER_DUE_SOON_DAYS: z.coerce.number().int().min(1).max(30).default(3),
+    RATE_LIMIT_WINDOW_SECONDS: z.coerce.number().int().min(1).default(60),
+    RATE_LIMIT_MAX_REQUESTS: z.coerce.number().int().min(1).default(300),
+    RATE_LIMIT_SENSITIVE_WINDOW_SECONDS: z.coerce
+      .number()
+      .int()
+      .min(1)
+      .default(60),
+    RATE_LIMIT_SENSITIVE_MAX_REQUESTS: z.coerce
+      .number()
+      .int()
+      .min(1)
+      .default(10),
+  })
+  .superRefine((value, context) => {
+    if (value.OIDC_ADMIN_ROLE && !value.OIDC_ROLES_CLAIM) {
+      context.addIssue({
+        code: 'custom',
+        path: ['OIDC_ROLES_CLAIM'],
+        message:
+          'OIDC_ROLES_CLAIM ist erforderlich, wenn OIDC_ADMIN_ROLE gesetzt ist.',
+      });
+    }
+  });
 
 export function loadConfigFromEnv(env: Record<string, unknown>): AppConfig {
   const parsed = envSchema.safeParse(env);
@@ -134,6 +178,9 @@ export function loadConfigFromEnv(env: Record<string, unknown>): AppConfig {
       scopes: value.OIDC_SCOPES,
       allowedAlgorithms: value.OIDC_ALLOWED_ALGORITHMS,
       httpTimeoutMs: value.OIDC_HTTP_TIMEOUT_MS,
+      roleMatchCaseSensitive: value.OIDC_ROLE_MATCH_CASE_SENSITIVE,
+      ...(value.OIDC_ADMIN_ROLE ? { adminRole: value.OIDC_ADMIN_ROLE } : {}),
+      ...(value.OIDC_ROLES_CLAIM ? { rolesClaim: value.OIDC_ROLES_CLAIM } : {}),
       ...(value.OIDC_LOGOUT_URL ? { logoutUrl: value.OIDC_LOGOUT_URL } : {}),
     },
     session: {
diff --git a/apps/backend/src/database/entities.ts b/apps/backend/src/database/entities.ts
index dc748b1..d3cdc60 100644
--- a/apps/backend/src/database/entities.ts
+++ b/apps/backend/src/database/entities.ts
@@ -11,6 +11,7 @@ import { PermissionEntity } from '../roles/entities/permission.entity';
 import { SessionEntity } from '../sessions/entities/session.entity';
 import { UserSettingsEntity } from '../users/entities/user-settings.entity';
 import { UserEntity } from '../users/entities/user.entity';
+import { UserRoleAssignmentEntity } from '../users/entities/user-role-assignment.entity';
 import {
   BudgetCategoryEntity,
   BuildingEntity,
@@ -49,6 +50,7 @@ export const entities = [
   SessionEntity,
   UserSettingsEntity,
   UserEntity,
+  UserRoleAssignmentEntity,
   BuildingEntity,
   FloorEntity,
   RoomEntity,
diff --git a/apps/backend/src/database/migrations/1720000008000-AddRoleAssignmentSources.ts b/apps/backend/src/database/migrations/1720000008000-AddRoleAssignmentSources.ts
new file mode 100644
index 0000000..086ca02
--- /dev/null
+++ b/apps/backend/src/database/migrations/1720000008000-AddRoleAssignmentSources.ts
@@ -0,0 +1,46 @@
+import type { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class AddRoleAssignmentSources1720000008000
+  implements MigrationInterface
+{
+  name = 'AddRoleAssignmentSources1720000008000';
+
+  async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      'ALTER TABLE roles ADD COLUMN role_key varchar(40) NULL AFTER id, ADD UNIQUE KEY uq_roles_role_key (role_key)',
+    );
+    await queryRunner.query(
+      "UPDATE roles SET role_key = 'ADMIN' WHERE name = 'admin'",
+    );
+    await queryRunner.query(
+      "UPDATE roles SET role_key = 'USER' WHERE name = 'user'",
+    );
+    await queryRunner.query(`
+      CREATE TABLE user_role_assignments (
+        id char(36) NOT NULL,
+        user_id char(36) NOT NULL,
+        role_id char(36) NOT NULL,
+        source varchar(20) NOT NULL,
+        last_synchronized_at datetime(3) NULL,
+        created_at datetime(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+        updated_at datetime(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
+        UNIQUE KEY uq_user_role_assignments_source (user_id, role_id, source),
+        KEY idx_user_role_assignments_user (user_id),
+        CONSTRAINT fk_user_role_assignments_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+        CONSTRAINT fk_user_role_assignments_role FOREIGN KEY (role_id) REFERENCES roles(id) ON DELETE CASCADE,
+        PRIMARY KEY (id)
+      ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
+    `);
+    await queryRunner.query(`
+      INSERT INTO user_role_assignments (id, user_id, role_id, source, last_synchronized_at)
+      SELECT UUID(), user_id, role_id, 'MANUAL', NULL FROM user_roles
+    `);
+  }
+
+  async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query('DROP TABLE user_role_assignments');
+    await queryRunner.query(
+      'ALTER TABLE roles DROP INDEX uq_roles_role_key, DROP COLUMN role_key',
+    );
+  }
+}
diff --git a/apps/backend/src/database/typeorm-cli.datasource.ts b/apps/backend/src/database/typeorm-cli.datasource.ts
index 1afbff5..5d98bcf 100644
--- a/apps/backend/src/database/typeorm-cli.datasource.ts
+++ b/apps/backend/src/database/typeorm-cli.datasource.ts
@@ -10,6 +10,7 @@ import { AddRenovationDomain1720000004000 } from './migrations/1720000004000-Add
 import { AddMentionsAndReminders1720000005000 } from './migrations/1720000005000-AddMentionsAndReminders';
 import { AddDefaultProjectFloors1720000006000 } from './migrations/1720000006000-AddDefaultProjectFloors';
 import { AddFurniturePlanning1720000007000 } from './migrations/1720000007000-AddFurniturePlanning';
+import { AddRoleAssignmentSources1720000008000 } from './migrations/1720000008000-AddRoleAssignmentSources';
 
 const config = loadConfigForCli();
 
@@ -35,5 +36,6 @@ export default new DataSource({
     AddMentionsAndReminders1720000005000,
     AddDefaultProjectFloors1720000006000,
     AddFurniturePlanning1720000007000,
+    AddRoleAssignmentSources1720000008000,
   ],
 });
diff --git a/apps/backend/src/database/typeorm-options.ts b/apps/backend/src/database/typeorm-options.ts
index 6e0ebc0..53d7266 100644
--- a/apps/backend/src/database/typeorm-options.ts
+++ b/apps/backend/src/database/typeorm-options.ts
@@ -9,6 +9,7 @@ import { AddRenovationDomain1720000004000 } from './migrations/1720000004000-Add
 import { AddMentionsAndReminders1720000005000 } from './migrations/1720000005000-AddMentionsAndReminders';
 import { AddDefaultProjectFloors1720000006000 } from './migrations/1720000006000-AddDefaultProjectFloors';
 import { AddFurniturePlanning1720000007000 } from './migrations/1720000007000-AddFurniturePlanning';
+import { AddRoleAssignmentSources1720000008000 } from './migrations/1720000008000-AddRoleAssignmentSources';
 
 export function typeOrmOptionsFactory(
   config: AppConfigService,
@@ -35,6 +36,7 @@ export function typeOrmOptionsFactory(
       AddMentionsAndReminders1720000005000,
       AddDefaultProjectFloors1720000006000,
       AddFurniturePlanning1720000007000,
+      AddRoleAssignmentSources1720000008000,
     ],
   };
 }
diff --git a/apps/backend/src/main.ts b/apps/backend/src/main.ts
index c1dfcb7..7c7551b 100644
--- a/apps/backend/src/main.ts
+++ b/apps/backend/src/main.ts
@@ -3,6 +3,7 @@ import cookieParser from 'cookie-parser';
 import type { NextFunction, Request, Response } from 'express';
 import helmet from 'helmet';
 import pinoHttp from 'pino-http';
+import { Logger } from '@nestjs/common';
 import { NestFactory } from '@nestjs/core';
 import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
 import type { NestExpressApplication } from '@nestjs/platform-express';
@@ -16,6 +17,11 @@ async function bootstrap() {
     bufferLogs: true,
   });
   const config = app.get(AppConfigService);
+  if (!config.oidc.adminRole) {
+    new Logger('Configuration').warn(
+      'OIDC_ADMIN_ROLE ist nicht konfiguriert. Die automatische Administrator-Synchronisierung ist deaktiviert; es gibt keinen First-User-Fallback.',
+    );
+  }
 
   app.use(
     pinoHttp({
diff --git a/apps/backend/src/notifications/tests/notification-integrations.spec.ts b/apps/backend/src/notifications/tests/notification-integrations.spec.ts
index 95cedd1..17e6ea5 100644
--- a/apps/backend/src/notifications/tests/notification-integrations.spec.ts
+++ b/apps/backend/src/notifications/tests/notification-integrations.spec.ts
@@ -65,11 +65,20 @@ describe('Notification integrations', () => {
       active: true,
       roles: [{ id: 'role-user', name: 'user' }],
     };
+    let userLoad = 0;
     const users: Pick<UsersRepository, 'findByIdWithRoles' | 'save'> = {
-      findByIdWithRoles: () =>
-        Promise.resolve(
-          user as Awaited<ReturnType<UsersRepository['findByIdWithRoles']>>,
-        ),
+      findByIdWithRoles: () => {
+        const loaded =
+          userLoad++ === 0
+            ? user
+            : {
+                ...user,
+                roles: [...user.roles, { id: 'role-editor', name: 'Editor' }],
+              };
+        return Promise.resolve(
+          loaded as Awaited<ReturnType<UsersRepository['findByIdWithRoles']>>,
+        );
+      },
       save: (entry) => Promise.resolve(entry),
     };
     const roles: Pick<RolesService, 'getRole'> = {
@@ -87,8 +96,28 @@ describe('Notification integrations', () => {
         );
       },
     };
+    const assignmentRepository = {
+      findBy: () =>
+        Promise.resolve([
+          { userId: 'user-1', roleId: 'role-user', source: 'MANUAL' },
+        ]),
+      remove: () => Promise.resolve(),
+      insert: () => Promise.resolve(),
+      createQueryBuilder: () => ({
+        select: () => ({
+          where: () => ({
+            getRawMany: () =>
+              Promise.resolve([
+                { roleId: 'role-user' },
+                { roleId: 'role-editor' },
+              ]),
+          }),
+        }),
+      }),
+    };
     const manager = {
       query: () => Promise.resolve(),
+      getRepository: () => assignmentRepository,
     } as unknown as EntityManager;
     const dataSource = {
       transaction: <T>(action: (manager: EntityManager) => Promise<T>) =>
diff --git a/apps/backend/src/roles/entities/role.entity.ts b/apps/backend/src/roles/entities/role.entity.ts
index 19c37c1..edf7a8c 100644
--- a/apps/backend/src/roles/entities/role.entity.ts
+++ b/apps/backend/src/roles/entities/role.entity.ts
@@ -17,6 +17,9 @@ export class RoleEntity {
   @PrimaryGeneratedColumn('uuid')
   id!: string;
 
+  @Column({ name: 'role_key', type: 'varchar', length: 40, nullable: true })
+  roleKey!: string | null;
+
   @Column({ type: 'varchar', length: 80 })
   name!: string;
 
diff --git a/apps/backend/src/roles/roles.service.ts b/apps/backend/src/roles/roles.service.ts
index 38b6341..fc3b47e 100644
--- a/apps/backend/src/roles/roles.service.ts
+++ b/apps/backend/src/roles/roles.service.ts
@@ -11,6 +11,8 @@ import { RoleEntity } from './entities/role.entity';
 import { allPermissions, Permission } from './permissions';
 import type { CreateRoleDto, UpdateRoleDto } from './dto/role.dto';
 import { RolesRepository } from './repositories/roles.repository';
+import { AppConfigService } from '../config/config.service';
+import { adminRoleKey, userRoleKey } from './system-role-keys';
 
 const adminRoleName = 'admin';
 const userRoleName = 'user';
@@ -20,6 +22,7 @@ export class RolesService {
   constructor(
     private readonly roles: RolesRepository,
     private readonly audit: AuditService,
+    private readonly config: AppConfigService,
     @InjectDataSource() private readonly dataSource: DataSource,
   ) {}
 
@@ -78,12 +81,12 @@ export class RolesService {
           await this.assertRoleNameAvailable(normalizedName, id, manager);
           role.name = normalizedName;
         }
-        if (role.name === adminRoleName) {
+        if (role.roleKey === adminRoleKey) {
           this.assertAdminPermissions(dto.permissions);
         }
         role.description = dto.description?.trim() ?? '';
         role.permissions = await this.loadPermissionEntities(
-          role.name === adminRoleName ? allPermissions : dto.permissions,
+          role.roleKey === adminRoleKey ? allPermissions : dto.permissions,
           manager,
         );
         const saved = await this.roles.save(role, manager);
@@ -178,12 +181,14 @@ export class RolesService {
     await this.syncPermissions(manager);
     const admin = await this.ensureRole(
       adminRoleName,
+      adminRoleKey,
       allPermissions,
       true,
       manager,
     );
     const user = await this.ensureRole(
       userRoleName,
+      userRoleKey,
       [
         Permission.ItemsRead,
         Permission.SessionsReadOwn,
@@ -223,6 +228,7 @@ export class RolesService {
 
   private async ensureRole(
     name: string,
+    roleKey: string,
     permissions: Permission[],
     protectedRole: boolean,
     manager?: EntityManager,
@@ -237,6 +243,7 @@ export class RolesService {
       role.name = name;
       role.protected = protectedRole;
     }
+    role.roleKey = roleKey;
     role.permissions = await this.loadPermissionEntities(permissions, manager);
     role.protected = protectedRole;
     return repo.save(role);
@@ -303,6 +310,13 @@ export class RolesService {
       description: role.description,
       system: role.protected,
       protected: role.protected,
+      roleKey: role.roleKey,
+      oidcManaged:
+        role.roleKey === adminRoleKey && Boolean(this.config.oidc.adminRole),
+      oidcRoleName:
+        role.roleKey === adminRoleKey
+          ? (this.config.oidc.adminRole ?? null)
+          : null,
       permissions: role.permissions,
       userCount: role.users?.length ?? 0,
       users: role.users,
diff --git a/apps/backend/src/roles/system-role-keys.ts b/apps/backend/src/roles/system-role-keys.ts
new file mode 100644
index 0000000..19f91fe
--- /dev/null
+++ b/apps/backend/src/roles/system-role-keys.ts
@@ -0,0 +1,2 @@
+export const adminRoleKey = 'ADMIN';
+export const userRoleKey = 'USER';
diff --git a/apps/backend/src/users/entities/user-role-assignment.entity.ts b/apps/backend/src/users/entities/user-role-assignment.entity.ts
new file mode 100644
index 0000000..6aee092
--- /dev/null
+++ b/apps/backend/src/users/entities/user-role-assignment.entity.ts
@@ -0,0 +1,46 @@
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  Index,
+  PrimaryGeneratedColumn,
+  Unique,
+  UpdateDateColumn,
+} from 'typeorm';
+
+export enum UserRoleAssignmentSource {
+  Manual = 'MANUAL',
+  Oidc = 'OIDC',
+  System = 'SYSTEM',
+}
+
+@Entity('user_role_assignments')
+@Unique('uq_user_role_assignments_source', ['userId', 'roleId', 'source'])
+@Index('idx_user_role_assignments_user', ['userId'])
+export class UserRoleAssignmentEntity {
+  @PrimaryGeneratedColumn('uuid')
+  id!: string;
+
+  @Column({ name: 'user_id', type: 'char', length: 36 })
+  userId!: string;
+
+  @Column({ name: 'role_id', type: 'char', length: 36 })
+  roleId!: string;
+
+  @Column({ type: 'varchar', length: 20 })
+  source!: UserRoleAssignmentSource;
+
+  @Column({
+    name: 'last_synchronized_at',
+    type: 'datetime',
+    precision: 3,
+    nullable: true,
+  })
+  lastSynchronizedAt!: Date | null;
+
+  @CreateDateColumn({ name: 'created_at', type: 'datetime', precision: 3 })
+  createdAt!: Date;
+
+  @UpdateDateColumn({ name: 'updated_at', type: 'datetime', precision: 3 })
+  updatedAt!: Date;
+}
diff --git a/apps/backend/src/users/repositories/users.repository.ts b/apps/backend/src/users/repositories/users.repository.ts
index 468b17b..5c0141d 100644
--- a/apps/backend/src/users/repositories/users.repository.ts
+++ b/apps/backend/src/users/repositories/users.repository.ts
@@ -6,6 +6,7 @@ import type {
   AdminUserSortField,
 } from '../dto/user.dto';
 import { UserEntity } from '../entities/user.entity';
+import { adminRoleKey } from '../../roles/system-role-keys';
 
 @Injectable()
 export class UsersRepository {
@@ -115,7 +116,7 @@ export class UsersRepository {
       .createQueryBuilder('user')
       .innerJoin('user.roles', 'role')
       .where('user.active = :active', { active: true })
-      .andWhere('role.name = :role', { role: 'admin' })
+      .andWhere('role.roleKey = :roleKey', { roleKey: adminRoleKey })
       .orderBy('user.createdAt', 'ASC');
     if (excludedUserId) {
       qb.andWhere('user.id <> :excludedUserId', { excludedUserId });
diff --git a/apps/backend/src/users/users.module.ts b/apps/backend/src/users/users.module.ts
index c20620c..71f055e 100644
--- a/apps/backend/src/users/users.module.ts
+++ b/apps/backend/src/users/users.module.ts
@@ -9,10 +9,15 @@ import { UserEntity } from './entities/user.entity';
 import { UsersRepository } from './repositories/users.repository';
 import { UsersController } from './users.controller';
 import { UsersService } from './users.service';
+import { UserRoleAssignmentEntity } from './entities/user-role-assignment.entity';
 
 @Module({
   imports: [
-    TypeOrmModule.forFeature([UserEntity, UserSettingsEntity]),
+    TypeOrmModule.forFeature([
+      UserEntity,
+      UserSettingsEntity,
+      UserRoleAssignmentEntity,
+    ]),
     RolesModule,
     AuditModule,
     SessionsModule,
diff --git a/apps/backend/src/users/users.service.ts b/apps/backend/src/users/users.service.ts
index 77b5d94..e1c864f 100644
--- a/apps/backend/src/users/users.service.ts
+++ b/apps/backend/src/users/users.service.ts
@@ -9,11 +9,16 @@ import { ErrorCode } from '../common/errors/error-codes';
 import { NotificationType } from '../notifications/notification-types';
 import { NotificationsService } from '../notifications/notifications.service';
 import { RolesService } from '../roles/roles.service';
+import { adminRoleKey } from '../roles/system-role-keys';
 import { RoleEntity } from '../roles/entities/role.entity';
 import { SessionsService } from '../sessions/sessions.service';
 import type { AdminSessionDto } from '../sessions/sessions.service';
 import { UserSettingsEntity } from './entities/user-settings.entity';
 import { UserEntity } from './entities/user.entity';
+import {
+  UserRoleAssignmentEntity,
+  UserRoleAssignmentSource,
+} from './entities/user-role-assignment.entity';
 import type { AdminUserListQueryDto } from './dto/user.dto';
 import { UsersRepository } from './repositories/users.repository';
 
@@ -22,6 +27,7 @@ interface AdminRoleSummary {
   name: string;
   description: string;
   system: boolean;
+  sources: UserRoleAssignmentSource[];
 }
 
 interface AdminUserListItem {
@@ -63,7 +69,7 @@ export class UsersService {
     const [users, total] = await this.users.adminSearch(query);
     const items = await Promise.all(
       users.map(async (user) => ({
-        ...this.toAdminListItem(user),
+        ...this.toAdminListItem(user, await this.roleSources(user.id)),
         activeSessionCount: await this.sessions.countActiveForUser(user.id),
       })),
     );
@@ -76,7 +82,7 @@ export class UsersService {
   ): Promise<AdminUserDetail> {
     const user = await this.getWithRoles(id);
     return {
-      ...this.toAdminListItem(user),
+      ...this.toAdminListItem(user, await this.roleSources(user.id)),
       activeSessionCount: await this.sessions.countActiveForUser(user.id),
       effectivePermissions: this.effectivePermissions(user),
       sessions: await this.sessions.listForAdmin(user.id, currentSessionId),
@@ -120,7 +126,7 @@ export class UsersService {
           409,
         );
       }
-      if (!active && this.hasRole(user, 'admin')) {
+      if (!active && this.hasRole(user, adminRoleKey)) {
         await this.assertAnotherActiveAdminRemains(userId, manager);
       }
       user.active = active;
@@ -151,14 +157,8 @@ export class UsersService {
     userId: string,
     roleId: string,
   ): Promise<UserEntity> {
-    const user = await this.getWithRoles(userId);
-    if (user.roles.some((role) => role.id === roleId)) {
-      return user;
-    }
-    return this.replaceRoles(actor, userId, [
-      ...user.roles.map((role) => role.id),
-      roleId,
-    ]);
+    const roleIds = await this.manualRoleIds(userId);
+    return this.replaceRoles(actor, userId, [...roleIds, roleId]);
   }
 
   async removeRole(
@@ -166,14 +166,11 @@ export class UsersService {
     userId: string,
     roleId: string,
   ): Promise<UserEntity> {
-    const user = await this.getWithRoles(userId);
-    if (!user.roles.some((role) => role.id === roleId)) {
-      return user;
-    }
+    const roleIds = await this.manualRoleIds(userId);
     return this.replaceRoles(
       actor,
       userId,
-      user.roles.filter((role) => role.id !== roleId).map((role) => role.id),
+      roleIds.filter((id) => id !== roleId),
     );
   }
 
@@ -235,7 +232,7 @@ export class UsersService {
       .innerJoin('user.roles', 'role')
       .where('user.active = :active', { active: true })
       .andWhere('user.id <> :excludedUserId', { excludedUserId })
-      .andWhere('role.name = :role', { role: 'admin' })
+      .andWhere('role.roleKey = :roleKey', { roleKey: adminRoleKey })
       .getCount();
     if (result < 1) {
       throw new ApiError(
@@ -254,16 +251,58 @@ export class UsersService {
     return this.withAdminLock(async (manager) => {
       const user = await this.getWithRoles(userId, manager);
       const previousRoleNames = new Set(user.roles.map((role) => role.name));
-      const previousRoleIds = new Set(user.roles.map((role) => role.id));
-      const roles = await Promise.all(
-        roleIds.map((id) => this.roles.getRole(id, manager)),
+      const previouslyAdmin = user.roles.some(
+        (role) => role.roleKey === adminRoleKey,
       );
-      const nextRoleNames = new Set(roles.map((role) => role.name));
-      user.roles = roles;
-      if (previousRoleNames.has('admin') && !nextRoleNames.has('admin')) {
+      const assignmentRepo = manager.getRepository(UserRoleAssignmentEntity);
+      const previousAssignments = await assignmentRepo.findBy({
+        userId,
+        source: UserRoleAssignmentSource.Manual,
+      });
+      const previousRoleIds = new Set(
+        previousAssignments.map((entry) => entry.roleId),
+      );
+      const roles = await Promise.all(
+        [...new Set(roleIds)].map((id) => this.roles.getRole(id, manager)),
+      );
+      const nextManualIds = new Set(roles.map((role) => role.id));
+      for (const assignment of previousAssignments) {
+        if (!nextManualIds.has(assignment.roleId))
+          await assignmentRepo.remove(assignment);
+      }
+      for (const role of roles) {
+        if (!previousRoleIds.has(role.id)) {
+          await assignmentRepo.insert({
+            userId,
+            roleId: role.id,
+            source: UserRoleAssignmentSource.Manual,
+            lastSynchronizedAt: null,
+          });
+        }
+      }
+      const effectiveRows = await assignmentRepo
+        .createQueryBuilder('assignment')
+        .select('DISTINCT assignment.roleId', 'roleId')
+        .where('assignment.userId = :userId', { userId })
+        .getRawMany<{ roleId: string }>();
+      const effectiveRoles = await Promise.all(
+        effectiveRows.map((entry) => this.roles.getRole(entry.roleId, manager)),
+      );
+      const nextRoleNames = new Set(effectiveRoles.map((role) => role.name));
+      if (
+        previouslyAdmin &&
+        !effectiveRoles.some((role) => role.roleKey === adminRoleKey)
+      ) {
         await this.assertAnotherActiveAdminRemains(userId, manager);
       }
-      const saved = await this.users.save(user, manager);
+      await manager.query('DELETE FROM user_roles WHERE user_id = ?', [userId]);
+      for (const role of effectiveRoles) {
+        await manager.query(
+          'INSERT INTO user_roles (user_id, role_id) VALUES (?, ?)',
+          [userId, role.id],
+        );
+      }
+      const saved = await this.getWithRoles(user.id, manager);
       await this.recordRoleAudit(actor, userId, previousRoleIds, roles);
       await this.notifyRoleChanges(userId, previousRoleNames, nextRoleNames);
       return saved;
@@ -333,7 +372,10 @@ export class UsersService {
     });
   }
 
-  private toAdminListItem(user: UserEntity): AdminUserListItem {
+  private toAdminListItem(
+    user: UserEntity,
+    sources: Map<string, UserRoleAssignmentSource[]>,
+  ): AdminUserListItem {
     return {
       id: user.id,
       name: user.name,
@@ -344,6 +386,7 @@ export class UsersService {
         name: role.name,
         description: role.description,
         system: role.protected,
+        sources: sources.get(role.id) ?? [],
       })),
       lastLoginAt: user.lastLoginAt?.toISOString() ?? null,
       createdAt: user.createdAt.toISOString(),
@@ -351,6 +394,34 @@ export class UsersService {
     };
   }
 
+  private async manualRoleIds(userId: string): Promise<string[]> {
+    const assignments = await this.dataSource
+      .getRepository(UserRoleAssignmentEntity)
+      .findBy({
+        userId,
+        source: UserRoleAssignmentSource.Manual,
+      });
+    return assignments.map((entry) => entry.roleId);
+  }
+
+  private async roleSources(
+    userId: string,
+  ): Promise<Map<string, UserRoleAssignmentSource[]>> {
+    const assignments = await this.dataSource
+      .getRepository(UserRoleAssignmentEntity)
+      .findBy({
+        userId,
+      });
+    const result = new Map<string, UserRoleAssignmentSource[]>();
+    for (const assignment of assignments) {
+      result.set(assignment.roleId, [
+        ...(result.get(assignment.roleId) ?? []),
+        assignment.source,
+      ]);
+    }
+    return result;
+  }
+
   private effectivePermissions(user: UserEntity): string[] {
     return Array.from(
       new Set(
@@ -361,8 +432,8 @@ export class UsersService {
     ).sort();
   }
 
-  private hasRole(user: UserEntity, roleName: string): boolean {
-    return user.roles.some((role) => role.name === roleName);
+  private hasRole(user: UserEntity, roleKey: string): boolean {
+    return user.roles.some((role) => role.roleKey === roleKey);
   }
 
   private async notifyRoleChanges(
diff --git a/apps/frontend/src/app/features/admin/admin-role-detail.page.spec.ts b/apps/frontend/src/app/features/admin/admin-role-detail.page.spec.ts
index 03a994d..93d8d0f 100644
--- a/apps/frontend/src/app/features/admin/admin-role-detail.page.spec.ts
+++ b/apps/frontend/src/app/features/admin/admin-role-detail.page.spec.ts
@@ -3,6 +3,7 @@ import { ActivatedRoute, Router } from '@angular/router';
 import { ApiClientService } from '@boilerplate/api-client';
 import { AdminRoleDetailPageComponent } from './admin-role-detail.page';
 import { adminPermissionGroups } from './admin-permissions';
+import { of } from 'rxjs';
 
 describe('AdminRoleDetailPageComponent', () => {
   it('groups permissions for the role editor', async () => {
@@ -31,4 +32,41 @@ describe('AdminRoleDetailPageComponent', () => {
     expect(element.textContent).toContain('Benutzer aktivieren');
     expect(element.textContent).toContain('notifications.manage');
   });
+
+  it('shows the environment-managed OIDC mapping for the system admin role', async () => {
+    await TestBed.configureTestingModule({
+      imports: [AdminRoleDetailPageComponent],
+      providers: [
+        {
+          provide: ActivatedRoute,
+          useValue: { snapshot: { paramMap: { get: () => 'admin-role' } } },
+        },
+        { provide: Router, useValue: { navigate: vi.fn() } },
+        {
+          provide: ApiClientService,
+          useValue: {
+            adminRole: () =>
+              of({
+                id: 'admin-role',
+                name: 'admin',
+                description: 'Administrator',
+                system: true,
+                protected: true,
+                roleKey: 'ADMIN',
+                oidcManaged: true,
+                oidcRoleName: 'hauspilot-admin',
+                permissions: [],
+              }),
+          },
+        },
+      ],
+    }).compileComponents();
+    const fixture = TestBed.createComponent(AdminRoleDetailPageComponent);
+    fixture.detectChanges();
+    const host = fixture.nativeElement as HTMLElement;
+
+    expect(host.textContent).toContain('Automatische OIDC-Verwaltung');
+    expect(host.textContent).toContain('hauspilot-admin');
+    expect(host.textContent).toContain('OIDC_ADMIN_ROLE');
+  });
 });
diff --git a/apps/frontend/src/app/features/admin/admin-role-detail.page.ts b/apps/frontend/src/app/features/admin/admin-role-detail.page.ts
index acfab26..3584ed5 100644
--- a/apps/frontend/src/app/features/admin/admin-role-detail.page.ts
+++ b/apps/frontend/src/app/features/admin/admin-role-detail.page.ts
@@ -31,6 +31,19 @@ import { adminPermissionGroups } from './admin-permissions';
           @if (role()?.system) {
             <span class="system">Systemrolle</span>
           }
+          @if (role()?.roleKey === 'ADMIN'; as isAdminRole) {
+            <aside class="oidc-notice">
+              <strong>Automatische OIDC-Verwaltung</strong>
+              @if (role()?.oidcManaged) {
+                <span
+                  >OIDC-Rolle: <code>{{ role()?.oidcRoleName }}</code></span
+                >
+                <small>Quelle: Umgebungsvariable OIDC_ADMIN_ROLE</small>
+              } @else {
+                <span>Die automatische Administrator-Synchronisierung ist nicht konfiguriert.</span>
+              }
+            </aside>
+          }
           <label>
             Name
             <input
@@ -168,6 +181,14 @@ import { adminPermissionGroups } from './admin-permissions';
         padding: 4px 8px;
         color: var(--color-text-secondary);
       }
+      .oidc-notice {
+        display: grid;
+        gap: 6px;
+        padding: 12px;
+        border: 1px solid var(--color-border);
+        border-radius: 8px;
+        background: var(--color-background);
+      }
       @media (min-width: 900px) {
         .groups {
           grid-template-columns: 1fr 1fr;
diff --git a/apps/frontend/src/app/features/admin/admin-user-detail.page.spec.ts b/apps/frontend/src/app/features/admin/admin-user-detail.page.spec.ts
new file mode 100644
index 0000000..73706b7
--- /dev/null
+++ b/apps/frontend/src/app/features/admin/admin-user-detail.page.spec.ts
@@ -0,0 +1,50 @@
+import { TestBed } from '@angular/core/testing';
+import { ActivatedRoute } from '@angular/router';
+import { ApiClientService, type AdminUserDetailDto, type RoleDto } from '@boilerplate/api-client';
+import { of } from 'rxjs';
+import { AdminUserDetailPageComponent } from './admin-user-detail.page';
+
+describe('AdminUserDetailPageComponent', () => {
+  it('shows OIDC role provenance and does not offer local removal without a manual source', async () => {
+    const adminRole = {
+      id: 'admin-role',
+      name: 'admin',
+      description: 'Administrator',
+      system: true,
+      protected: true,
+      roleKey: 'ADMIN',
+      oidcManaged: true,
+      oidcRoleName: 'hauspilot-admin',
+      permissions: [],
+    } satisfies RoleDto;
+    const user = {
+      id: 'user-1',
+      name: 'Bastian',
+      email: 'admin@example.test',
+      active: true,
+      roles: [{ id: adminRole.id, name: 'admin', system: true, sources: ['OIDC'] }],
+      lastLoginAt: '2026-07-20',
+      createdAt: '2026-07-20',
+      activeSessionCount: 0,
+      effectivePermissions: [],
+      sessions: [],
+    } satisfies AdminUserDetailDto;
+    await TestBed.configureTestingModule({
+      imports: [AdminUserDetailPageComponent],
+      providers: [
+        { provide: ActivatedRoute, useValue: { snapshot: { paramMap: { get: () => user.id } } } },
+        {
+          provide: ApiClientService,
+          useValue: { adminRoles: () => of([adminRole]), adminUser: () => of(user) },
+        },
+      ],
+    }).compileComponents();
+    const fixture = TestBed.createComponent(AdminUserDetailPageComponent);
+    fixture.detectChanges();
+    const host = fixture.nativeElement as HTMLElement;
+
+    expect(host.textContent).toContain('Herkunft: OIDC');
+    expect(host.textContent).toContain('Entfernen Sie die externe Rolle im Identity Provider');
+    expect(host.textContent).not.toContain('Manuelle Zuweisung entfernen');
+  });
+});
diff --git a/apps/frontend/src/app/features/admin/admin-user-detail.page.ts b/apps/frontend/src/app/features/admin/admin-user-detail.page.ts
index 8101797..52f0234 100644
--- a/apps/frontend/src/app/features/admin/admin-user-detail.page.ts
+++ b/apps/frontend/src/app/features/admin/admin-user-detail.page.ts
@@ -50,11 +50,20 @@ import {
           <h3>Rollen</h3>
           <div class="chips">
             @for (role of currentUser.roles; track role.id) {
-              <span>
-                {{ role.name }}
-                <button type="button" (click)="removeRole(currentUser.id, role.id, role.name)">
-                  Entfernen
-                </button>
+              <span class="role-chip">
+                <span>
+                  <strong>{{ role.name }}</strong>
+                  <small>Herkunft: {{ roleSourceLabel(role.sources) }}</small>
+                </span>
+                @if (role.sources.includes('MANUAL')) {
+                  <button type="button" (click)="removeRole(currentUser.id, role.id, role.name)">
+                    Manuelle Zuweisung entfernen
+                  </button>
+                } @else if (role.sources.includes('OIDC')) {
+                  <small class="managed-hint">
+                    Automatisch verwaltet. Entfernen Sie die externe Rolle im Identity Provider.
+                  </small>
+                }
               </span>
             }
           </div>
@@ -203,6 +212,13 @@ import {
         border-radius: 999px;
         padding: 4px 6px 4px 10px;
       }
+      .role-chip > span {
+        display: grid;
+      }
+      .managed-hint {
+        max-width: 20rem;
+        color: var(--color-text-muted);
+      }
       .chips button {
         min-height: 34px;
         background: var(--color-danger);
@@ -323,8 +339,15 @@ export class AdminUserDetailPageComponent {
   }
 
   availableRoles(user: AdminUserDetailDto): RoleDto[] {
-    const assigned = new Set(user.roles.map((role) => role.id));
-    return this.roles().filter((role) => !assigned.has(role.id));
+    const manuallyAssigned = new Set(
+      user.roles.filter((role) => role.sources.includes('MANUAL')).map((role) => role.id),
+    );
+    return this.roles().filter((role) => !manuallyAssigned.has(role.id));
+  }
+
+  roleSourceLabel(sources: AdminUserDetailDto['roles'][number]['sources']): string {
+    const labels = { MANUAL: 'Manuell', OIDC: 'OIDC', SYSTEM: 'System' } as const;
+    return sources.map((source) => labels[source]).join(' + ');
   }
 
   messageFor(error: ApiErrorBody): string {
diff --git a/docs/admin.md b/docs/admin.md
index 9af20ac..7623da5 100644
--- a/docs/admin.md
+++ b/docs/admin.md
@@ -1,5 +1,9 @@
 # Adminbereich
 
+Die Systemrolle `ADMIN` kann aus den getrennten Quellen `MANUAL` und `OIDC` wirksam sein. Die
+Benutzerverwaltung zeigt die Herkunft; das externe Mapping ist nur über die Umgebung konfigurierbar.
+Siehe [Administratoren über OIDC](oidc-administrator.md).
+
 Der Adminbereich liegt im Frontend unter `/admin` und verwendet dieselbe
 serverseitige Authentifizierung, CSRF-Pruefung und Permission-Logik wie die
 restliche Anwendung. Angular blendet Navigation und Aktionen nur fuer passende
diff --git a/docs/configuration.md b/docs/configuration.md
index 6ebd6ba..5a7694e 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -1,5 +1,8 @@
 # Konfiguration
 
+Die globale Administratorrolle wird serverseitig über `OIDC_ADMIN_ROLE` und `OIDC_ROLES_CLAIM`
+synchronisiert. Details stehen unter [Administratoren über OIDC](oidc-administrator.md).
+
 Die Runtime-Konfiguration wird ueber Umgebungsvariablen geladen und mit Zod in
 `apps/backend/src/config/env.ts` validiert. `.env.example` ist die Referenz fuer
 lokale Entwicklung und Deployment-Vorlagen.
diff --git a/docs/oidc-administrator.md b/docs/oidc-administrator.md
new file mode 100644
index 0000000..61d2c4a
--- /dev/null
+++ b/docs/oidc-administrator.md
@@ -0,0 +1,63 @@
+# Administratoren über OIDC
+
+HausPilot synchronisiert die globale lokale Systemrolle mit dem stabilen Schlüssel `ADMIN` bei
+jedem erfolgreichen vollständigen OIDC-Login. Die Reihenfolge der Anmeldungen spielt keine Rolle;
+der frühere Mechanismus „erster Benutzer wird Administrator“ existiert nicht mehr.
+
+## Konfiguration
+
+```env
+OIDC_ADMIN_ROLE=hauspilot-admin
+OIDC_ROLES_CLAIM=roles
+OIDC_ROLE_MATCH_CASE_SENSITIVE=true
+```
+
+`OIDC_ADMIN_ROLE` enthält den exakten externen Rollennamen und hat bewusst keinen Standardwert.
+`OIDC_ROLES_CLAIM` unterstützt einfache und verschachtelte Pfade wie `roles`, `groups`,
+`realm_access.roles` oder `resource_access.hauspilot.roles`. Der Claim darf ein String oder ein
+Array aus Strings sein; Leerwerte und Duplikate werden entfernt.
+
+Ist `OIDC_ADMIN_ROLE` leer oder nicht gesetzt, protokolliert der Start eine Warnung. HausPilot
+fügt dann keine OIDC-Administratorzuweisung hinzu und entfernt auch keine bestehende. Ein gesetztes
+`OIDC_ADMIN_ROLE` ohne gültiges `OIDC_ROLES_CLAIM` führt zu einem Startfehler.
+
+## Synchronisierung und Fail-Safe-Verhalten
+
+Nach Signatur-, Issuer-, Audience- und Nonce-Prüfung des ID Tokens werden dessen Claims mit der
+subject-geprüften UserInfo zusammengeführt. Enthält der lesbare Rollenclaim `OIDC_ADMIN_ROLE`, wird
+die Quelle `OIDC` für die lokale Administratorrolle sichergestellt. Fehlt die Rolle in einer
+gültigen Rollenliste, wird nur diese OIDC-Quelle entfernt.
+
+Fehlt der konfigurierte Claim technisch oder hat er ein ungültiges Format, wird keine Zuweisung
+verändert und der Login fail-safe abgebrochen. Tokens und vollständige Claims werden weder
+protokolliert noch zusätzlich gespeichert. Die Synchronisierung geschieht vor dem Erzeugen der
+Session. Es gibt derzeit keinen Token-Refresh mit erneuter Claim-Validierung; Änderungen werden
+beim nächsten vollständigen Login wirksam.
+
+## Quellenmodell und Migration
+
+`user_role_assignments` speichert für Benutzer, Rolle und Quelle eine eindeutige Zuweisung mit den
+Quellen `MANUAL`, `OIDC` und `SYSTEM`. `user_roles` bleibt die effektive Projektion für bestehende
+Berechtigungsabfragen. Die Migration übernimmt alle vorhandenen Zuordnungen als `MANUAL`; keine
+bestehende Administratorrolle wird rückwirkend als OIDC interpretiert. Ein Unique Constraint
+verhindert doppelte Quellen bei parallelen Logins.
+
+Die Benutzerverwaltung zeigt die Herkunft an. Eine reine OIDC-Zuweisung lässt sich lokal nicht
+entfernen; die externe Rolle muss im Identity Provider entzogen werden. Bei `MANUAL + OIDC` kann
+die manuelle Quelle separat entfernt werden. Projektrollen und der Zugriff auf private Projekte
+bleiben unverändert.
+
+## Erstkonfiguration und Recovery
+
+1. Im Identity Provider eine Adminrolle anlegen und mindestens zwei Recovery-fähigen Benutzern geben.
+2. `OIDC_ADMIN_ROLE` und `OIDC_ROLES_CLAIM` in der Serverumgebung setzen.
+3. Migrationen kontrolliert mit `npm run migration:run` ausführen und die Anwendung neu starten.
+4. Benutzer vollständig neu anmelden.
+
+Änderungen des Rollennamens werden pro Benutzer beim nächsten Login wirksam. Wird die Variable
+geleert, bleiben bestehende OIDC-Zuweisungen bewusst erhalten. Für Notfälle kann eine kontrollierte
+Datenbankoperation oder ein separater, nicht öffentlicher CLI-Prozess eine `MANUAL`-Zuweisung
+setzen. Es gibt keine öffentliche Recovery-Route und keinen First-User-Fallback.
+
+Tatsächliche Änderungen werden als `OIDC_ADMIN_ASSIGNED` beziehungsweise `OIDC_ADMIN_REMOVED`
+auditiert; der externe Rollenname darf erscheinen, niemals Tokens oder vollständige Claims.
diff --git a/docs/security.md b/docs/security.md
index 2b764ec..6f0aba0 100644
--- a/docs/security.md
+++ b/docs/security.md
@@ -1,5 +1,9 @@
 # Security-Modell
 
+Globale Administratorrechte werden beim Login ausschließlich aus serverseitig validierten
+OIDC-Claims synchronisiert. Es gibt keine browserseitige Rollenübermittlung und keinen
+First-User-Admin-Fallback. Details: [Administratoren über OIDC](oidc-administrator.md).
+
 Das Boilerplate trennt Browser, Backend und Identity Provider strikt. Der Browser
 bekommt keine OIDC-Tokens. Das Backend ist fuer Authentifizierung,
 Autorisierung, CSRF und Session-Verwaltung verbindlich.
diff --git a/packages/api-client/src/models.ts b/packages/api-client/src/models.ts
index da2004b..0dce6b8 100644
--- a/packages/api-client/src/models.ts
+++ b/packages/api-client/src/models.ts
@@ -47,6 +47,7 @@ export interface AdminRoleSummaryDto {
   id: string;
   name: string;
   system: boolean;
+  sources: ('MANUAL' | 'OIDC' | 'SYSTEM')[];
 }
 
 export interface AdminSessionDto {
@@ -82,6 +83,9 @@ export interface RoleDto {
   description: string;
   system: boolean;
   protected: boolean;
+  roleKey: string | null;
+  oidcManaged: boolean;
+  oidcRoleName: string | null;
   permissions: { id: Permission; description: string }[];
   userCount?: number;
   users?: UserDto[];
diff --git a/scripts/generate-api-client.mjs b/scripts/generate-api-client.mjs
index 2aa0389..6063fd1 100644
--- a/scripts/generate-api-client.mjs
+++ b/scripts/generate-api-client.mjs
@@ -59,6 +59,7 @@ export interface AdminRoleSummaryDto {
   id: string;
   name: string;
   system: boolean;
+  sources: ('MANUAL' | 'OIDC' | 'SYSTEM')[];
 }
 
 export interface AdminSessionDto {
@@ -94,6 +95,9 @@ export interface RoleDto {
   description: string;
   system: boolean;
   protected: boolean;
+  roleKey: string | null;
+  oidcManaged: boolean;
+  oidcRoleName: string | null;
   permissions: { id: Permission; description: string }[];
   userCount?: number;
   users?: UserDto[];