diff --git a/backend/src/Controller/ImpersonationController.php b/backend/src/Controller/ImpersonationController.php
new file mode 100644
index 0000000..3f137ca
--- /dev/null
+++ b/backend/src/Controller/ImpersonationController.php
@@ -0,0 +1,85 @@
+<?php
+
+namespace App\Controller;
+
+use App\Entity\Employee;
+use App\Security\TenantContext;
+use App\Service\RoleService;
+use Doctrine\ORM\EntityManagerInterface;
+use Lexik\Bundle\JWTAuthenticationBundle\Services\JWTTokenManagerInterface;
+use Symfony\Bundle\SecurityBundle\Security;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+use Symfony\Component\Uid\Uuid;
+
+/**
+ * „Arbeiten als" (Impersonation), nur absteigend & im eigenen Mandanten-Teilbaum:
+ * gibt ein JWT für den Ziel-Mitarbeiter aus (mit imp-Claim für Audit).
+ */
+#[IsGranted('ROLE_COMPANY_ADMIN')]
+final class ImpersonationController
+{
+    public function __construct(
+        private readonly EntityManagerInterface $em,
+        private readonly RoleService $roles,
+        private readonly TenantContext $tenant,
+        private readonly JWTTokenManagerInterface $jwt,
+        private readonly Security $security,
+    ) {
+    }
+
+    #[Route('/api/impersonate/{id}', name: 'impersonate', methods: ['POST'])]
+    public function __invoke(string $id): JsonResponse
+    {
+        $target = $this->em->getRepository(Employee::class)->find(Uuid::fromString($id));
+        if (!$target instanceof Employee) {
+            throw new NotFoundHttpException('Mitarbeiter nicht gefunden.');
+        }
+        if (!$target->hasLogin()) {
+            throw new BadRequestHttpException('Dieser Mitarbeiter hat kein Login.');
+        }
+
+        $this->assertInScope($target);
+
+        // Nur absteigend: Ziel-Ebene muss unter der eigenen liegen
+        if ($this->roles->levelOfRoles($target->getRoles()) >= $this->roles->actorLevel()) {
+            throw new AccessDeniedHttpException('Nur als niedrigere Ebene möglich.');
+        }
+
+        $actor = $this->security->getUser();
+        $impersonator = $actor instanceof Employee ? $actor->getUserIdentifier() : '';
+
+        $token = $this->jwt->createFromPayload($target, ['imp' => $impersonator]);
+
+        return new JsonResponse([
+            'token' => $token,
+            'actingAs' => [
+                'name' => trim($target->getFirstName().' '.$target->getLastName()),
+                'email' => $target->getLoginEmail(),
+            ],
+        ]);
+    }
+
+    private function assertInScope(Employee $target): void
+    {
+        if ($this->tenant->isPlatformAdmin()) {
+            return;
+        }
+        if (null !== $company = $this->tenant->getCompany()) {
+            if (!$target->getCompany()->getId()->equals($company->getId())) {
+                throw new AccessDeniedHttpException('Außerhalb der eigenen Firma.');
+            }
+
+            return;
+        }
+        if (null !== $reseller = $this->tenant->getReseller()) {
+            if ($target->getCompany()->getReseller()?->getId()->equals($reseller->getId()) !== true) {
+                throw new AccessDeniedHttpException('Außerhalb des eigenen Resellers.');
+            }
+        }
+    }
+}
diff --git a/backend/src/Service/RoleService.php b/backend/src/Service/RoleService.php
index 42e7b40..9a9d1de 100644
--- a/backend/src/Service/RoleService.php
+++ b/backend/src/Service/RoleService.php
@@ -52,6 +52,19 @@ final class RoleService
         return 0;
     }
 
+    /** Höchste Ebene aus einer Rollenliste (z. B. eines Ziel-Mitarbeiters). */
+    public function levelOfRoles(array $roles): int
+    {
+        $level = 0;
+        foreach (self::GROUPS as $g) {
+            if (in_array($g['role'], $roles, true)) {
+                $level = max($level, $g['level']);
+            }
+        }
+
+        return $level;
+    }
+
     /** Rechtegruppen, die der Akteur vergeben darf (≤ eigene Ebene). */
     public function assignableGroups(): array
     {
diff --git a/frontend/src/layouts/DashboardLayout.vue b/frontend/src/layouts/DashboardLayout.vue
index 586bceb..dad0db0 100644
--- a/frontend/src/layouts/DashboardLayout.vue
+++ b/frontend/src/layouts/DashboardLayout.vue
@@ -29,6 +29,11 @@ function logout() {
   auth.logout()
   router.push('/login')
 }
+
+async function stopImpersonation() {
+  await auth.stopImpersonation()
+  router.push('/app')
+}
 </script>
 
 <template>
@@ -48,6 +53,10 @@ function logout() {
     </aside>
 
     <div class="main">
+      <div v-if="auth.isImpersonating" class="imp-banner">
+        <span>Du arbeitest als <strong>{{ auth.actingAs?.name }}</strong> ({{ auth.actingAs?.email }})</span>
+        <button class="btn btn-sm" @click="stopImpersonation">Beenden</button>
+      </div>
       <header class="topbar">
         <div class="topbar__ctx">
           <span class="muted">Mandant</span>
@@ -82,6 +91,8 @@ function logout() {
 .navlink.active { background: var(--psc-orange); color: #fff; }
 
 .main { flex: 1; display: flex; flex-direction: column; min-width: 0; }
+.imp-banner { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: .55rem 1.6rem; background: var(--psc-orange); color: #fff; font-size: .9rem; font-weight: 600; }
+.imp-banner .btn { background: #fff; color: var(--psc-orange-dark); }
 .topbar {
   display: flex; align-items: center; justify-content: space-between;
   padding: 1rem 1.6rem; background: #fff; border-bottom: 1px solid var(--line);
diff --git a/frontend/src/stores/auth.ts b/frontend/src/stores/auth.ts
index 3011327..a646b5e 100644
--- a/frontend/src/stores/auth.ts
+++ b/frontend/src/stores/auth.ts
@@ -15,17 +15,28 @@ export interface CurrentUser {
   company: TenantRef | null
 }
 
+const ROLE_LEVEL: Record<string, number> = {
+  ROLE_PLATFORM_ADMIN: 3,
+  ROLE_RESELLER_ADMIN: 2,
+  ROLE_COMPANY_ADMIN: 1,
+  ROLE_EMPLOYEE: 0,
+}
+
 export const useAuthStore = defineStore('auth', () => {
   const token = ref<string | null>(localStorage.getItem('token'))
-  const user = ref<CurrentUser | null>(
-    JSON.parse(localStorage.getItem('user') || 'null'),
+  const user = ref<CurrentUser | null>(JSON.parse(localStorage.getItem('user') || 'null'))
+  const actingAs = ref<{ name: string; email: string } | null>(
+    JSON.parse(localStorage.getItem('actingAs') || 'null'),
   )
+  const originalToken = ref<string | null>(localStorage.getItem('token_original'))
 
   const isAuthenticated = computed(() => !!token.value)
   const roles = computed(() => user.value?.roles ?? [])
   const isPlatformAdmin = computed(() => roles.value.includes('ROLE_PLATFORM_ADMIN'))
   const isResellerAdmin = computed(() => roles.value.includes('ROLE_RESELLER_ADMIN'))
   const isCompanyAdmin = computed(() => roles.value.includes('ROLE_COMPANY_ADMIN'))
+  const level = computed(() => Math.max(0, ...roles.value.map((r) => ROLE_LEVEL[r] ?? -1)))
+  const isImpersonating = computed(() => !!originalToken.value)
 
   async function login(email: string, password: string) {
     const { data } = await client.post('/login', { email, password })
@@ -40,16 +51,45 @@ export const useAuthStore = defineStore('auth', () => {
     localStorage.setItem('user', JSON.stringify(data))
   }
 
+  // „Arbeiten als" – tauscht das Token gegen ein impersoniertes (absteigend, backend-geprüft)
+  async function impersonate(employeeId: string) {
+    const { data } = await client.post(`/impersonate/${employeeId}`)
+    if (!originalToken.value) {
+      originalToken.value = token.value ?? ''
+      localStorage.setItem('token_original', originalToken.value)
+    }
+    token.value = data.token
+    localStorage.setItem('token', data.token)
+    actingAs.value = data.actingAs
+    localStorage.setItem('actingAs', JSON.stringify(data.actingAs))
+    await fetchMe()
+  }
+
+  async function stopImpersonation() {
+    if (!originalToken.value) return
+    token.value = originalToken.value
+    localStorage.setItem('token', originalToken.value)
+    originalToken.value = null
+    localStorage.removeItem('token_original')
+    localStorage.removeItem('actingAs')
+    actingAs.value = null
+    await fetchMe()
+  }
+
   function logout() {
     token.value = null
     user.value = null
+    actingAs.value = null
+    originalToken.value = null
     localStorage.removeItem('token')
     localStorage.removeItem('user')
+    localStorage.removeItem('token_original')
+    localStorage.removeItem('actingAs')
   }
 
   return {
-    token, user, isAuthenticated, roles,
-    isPlatformAdmin, isResellerAdmin, isCompanyAdmin,
-    login, fetchMe, logout,
+    token, user, actingAs, isAuthenticated, roles, level,
+    isPlatformAdmin, isResellerAdmin, isCompanyAdmin, isImpersonating,
+    login, fetchMe, impersonate, stopImpersonation, logout,
   }
 })
diff --git a/frontend/src/views/UsersView.vue b/frontend/src/views/UsersView.vue
index 4f6d81b..0c43a8d 100644
--- a/frontend/src/views/UsersView.vue
+++ b/frontend/src/views/UsersView.vue
@@ -1,6 +1,8 @@
 <script setup lang="ts">
 import { ref, onMounted } from 'vue'
+import { useRouter } from 'vue-router'
 import client from '@/api/client'
+import { useAuthStore } from '@/stores/auth'
 
 interface LoginRow {
   employeeId: string; email: string; name: string; group: string
@@ -12,10 +14,23 @@ const GROUP_LABEL: Record<string, string> = {
   platform_admin: 'Plattform-Admin', reseller_admin: 'Reseller-Admin',
   company_admin: 'Firmen-Admin', employee: 'Mitarbeiter',
 }
+const GROUP_LEVEL: Record<string, number> = {
+  platform_admin: 3, reseller_admin: 2, company_admin: 1, employee: 0,
+}
 
+const auth = useAuthStore()
+const router = useRouter()
 const rows = ref<LoginRow[]>([])
 const loading = ref(true)
 
+function canWorkAs(r: LoginRow) {
+  return GROUP_LEVEL[r.group] < auth.level && r.employeeId !== auth.user?.id
+}
+async function workAs(r: LoginRow) {
+  await auth.impersonate(r.employeeId)
+  router.push('/app')
+}
+
 async function load() {
   loading.value = true
   rows.value = (await client.get('/users')).data.member
@@ -47,7 +62,10 @@ onMounted(load)
             <td>{{ r.name }}</td>
             <td><span class="badge badge-role">{{ GROUP_LABEL[r.group] ?? r.group }}</span></td>
             <td class="muted">{{ r.company?.name ?? r.reseller?.name ?? 'Plattform' }}</td>
-            <td class="right"><button class="btn btn-ghost btn-sm" @click="revoke(r)">Login entfernen</button></td>
+            <td class="right">
+              <button v-if="canWorkAs(r)" class="btn btn-soft btn-sm" @click="workAs(r)">Arbeiten als</button>
+              <button class="btn btn-ghost btn-sm" @click="revoke(r)">Login entfernen</button>
+            </td>
           </tr>
         </tbody>
       </table>