diff --git a/backend/app/models/user.py b/backend/app/models/user.py
index 38d2470..6bcb939 100644
--- a/backend/app/models/user.py
+++ b/backend/app/models/user.py
@@ -57,6 +57,9 @@ class User(Base):
     # Pro-User-Benachrichtigungseinstellungen (agent-11 PR3). Leeres dict = alle an.
     notification_prefs: Mapped[dict] = mapped_column(JSONB, nullable=False, default=dict, server_default="{}")
 
+    # DSGVO Art. 17: Zeitpunkt der Anonymisierung (Personenbezug entfernt). NULL = aktiv.
+    anonymized_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+
     # Kiosk auth
     kiosk_pin_hash: Mapped[str | None] = mapped_column(Text)
     kiosk_qr_token: Mapped[str | None] = mapped_column(Text, unique=True)
diff --git a/backend/app/routers/users.py b/backend/app/routers/users.py
index 041c686..14db172 100644
--- a/backend/app/routers/users.py
+++ b/backend/app/routers/users.py
@@ -232,6 +232,18 @@ async def reactivate_user(
     return UserOut.model_validate(user)
 
 
+@router.post("/{user_id}/anonymize", response_model=UserOut)
+async def anonymize_user(
+    user_id: UUID,
+    current_user: User = require_role(*_admin_roles),
+    db: AsyncSession = Depends(get_db),
+):
+    """DSGVO Art. 17: Personenbezug des Kontos entfernen (nicht umkehrbar).
+    Referenzierte Daten (Zeit/Abwesenheit/Auszahlung) bleiben entkoppelt erhalten."""
+    user = await user_service.anonymize_user(user_id, current_user, db)
+    return UserOut.model_validate(user)
+
+
 @router.post("/{user_id}/kiosk-pin", response_model=MessageResponse)
 async def set_kiosk_pin(
     user_id: UUID,
diff --git a/backend/app/schemas/user.py b/backend/app/schemas/user.py
index 7c3a327..39dfd64 100644
--- a/backend/app/schemas/user.py
+++ b/backend/app/schemas/user.py
@@ -30,6 +30,7 @@ class UserOut(BaseModel):
     work_schedule_id: uuid.UUID | None = None
     entry_date: date | None = None
     exit_date: date | None = None
+    anonymized_at: datetime | None = None
 
 
 class NotificationTypeOut(BaseModel):
diff --git a/backend/app/services/user_service.py b/backend/app/services/user_service.py
index 44dac9e..62a27f2 100644
--- a/backend/app/services/user_service.py
+++ b/backend/app/services/user_service.py
@@ -335,9 +335,57 @@ class UserService:
 
     async def reactivate(self, user_id: UUID, current_user: User, db: AsyncSession) -> User:
         user = await self.get_by_id(user_id, current_user.company_id, db)
+        if user.anonymized_at is not None:
+            raise HTTPException(status_code=409, detail="Anonymisierte Konten können nicht reaktiviert werden.")
         user.is_active = True
         return user
 
+    async def anonymize_user(self, user_id: UUID, current_user: User, db: AsyncSession) -> User:
+        """DSGVO Art. 17: Personenbezug eines Users entfernen (statt Hard-Delete).
+
+        Die User-Zeile + alle Referenzen (Zeit, Abwesenheit, Auszahlungen, AuditLog)
+        bleiben für die gesetzliche Aufbewahrung erhalten, verlieren aber den Personenbezug.
+        Personalnummer bleibt reserviert. Nicht umkehrbar.
+        """
+        if user_id == current_user.id:
+            raise HTTPException(status_code=400, detail="Das eigene Konto kann nicht anonymisiert werden.")
+        user = await self.get_by_id(user_id, current_user.company_id, db)
+        if user.anonymized_at is not None:
+            raise HTTPException(status_code=409, detail="Konto ist bereits anonymisiert.")
+
+        old = {"first_name": user.first_name, "last_name": user.last_name, "email": user.email}
+
+        # Personenbezogene Felder überschreiben / Auth-Material entfernen
+        user.first_name = "Anonymisiert"
+        user.last_name = str(user.id)[:8]
+        user.email = f"anon-{user.id}@deleted.local"
+        user.password_hash = None
+        user.kiosk_pin_hash = None
+        user.kiosk_qr_token = None
+        user.kiosk_nfc_uid = None
+        user.totp_secret = None
+        user.totp_enabled = False
+        user.ldap_dn = None
+        user.kuerzel = None
+        user.invite_token_hash = None
+        user.is_active = False
+        user.anonymized_at = datetime.now(timezone.utc)
+        # personnel_number bleibt erhalten (reserviert, kein Personenbezug mehr)
+
+        # Aktive Sessions des Users beenden (Refresh-Tokens entwerten)
+        await db.execute(text("DELETE FROM sessions WHERE user_id = :uid"), {"uid": str(user.id)})
+
+        db.add(AuditLog(
+            company_id=current_user.company_id,
+            user_id=current_user.id,
+            action="user_anonymized",
+            entity_type="user",
+            entity_id=user.id,
+            old_value=old,
+            new_value={"anonymized_at": user.anonymized_at.isoformat(), "target_user_id": str(user.id)},
+        ))
+        return user
+
     # ── Kiosk ─────────────────────────────────────────────────────────────────
 
     async def set_kiosk_pin(self, user: User, pin: str, db: AsyncSession) -> None:
diff --git a/backend/migrations/versions/0040_user_anonymization.py b/backend/migrations/versions/0040_user_anonymization.py
new file mode 100644
index 0000000..826ca4c
--- /dev/null
+++ b/backend/migrations/versions/0040_user_anonymization.py
@@ -0,0 +1,23 @@
+"""DSGVO Art. 17: users.anonymized_at
+
+Revision ID: 0040
+Revises: 0039
+Create Date: 2026-06-23
+
+Markiert anonymisierte Konten (Personenbezug entfernt, Zeile + Referenzen bleiben
+für die gesetzliche Aufbewahrung erhalten). NULL = aktives Konto.
+"""
+from alembic import op
+
+revision = "0040"
+down_revision = "0039"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.execute("ALTER TABLE users ADD COLUMN IF NOT EXISTS anonymized_at TIMESTAMPTZ")
+
+
+def downgrade() -> None:
+    op.execute("ALTER TABLE users DROP COLUMN IF EXISTS anonymized_at")
diff --git a/backend/tests/test_users.py b/backend/tests/test_users.py
index dea2396..3caae1f 100644
--- a/backend/tests/test_users.py
+++ b/backend/tests/test_users.py
@@ -126,3 +126,38 @@ async def test_kiosk_pin_must_be_numeric(client: AsyncClient, registered_user):
         json={"pin": "abcd"},
     )
     assert resp.status_code == 422
+
+
+async def test_anonymize_user(client: AsyncClient, registered_user):
+    """DSGVO Art. 17: Anonymisierung entfernt den Personenbezug, Konto wird inaktiv."""
+    inv = await client.post(INVITE_URL, headers=auth(registered_user["tokens"]), json={
+        "email": "gdpr@test.de", "first_name": "Max", "last_name": "Muster",
+        "role": "EMPLOYEE", "initial_password": "Secret123",
+    })
+    user_id = inv.json()["id"]
+
+    resp = await client.post(f"{USERS_URL}/{user_id}/anonymize", headers=auth(registered_user["tokens"]))
+    assert resp.status_code == 200, resp.text
+    body = resp.json()
+    assert body["anonymized_at"] is not None
+    assert body["first_name"] == "Anonymisiert"
+    assert body["email"] == f"anon-{user_id}@deleted.local"
+    assert body["is_active"] is False
+
+    # Login mit alter E-Mail unmöglich
+    login = await client.post("/api/v1/auth/login", json={"email": "gdpr@test.de", "password": "Secret123"})
+    assert login.status_code == 401
+
+    # Reaktivierung eines anonymisierten Kontos wird abgelehnt
+    react = await client.post(f"{USERS_URL}/{user_id}/reactivate", headers=auth(registered_user["tokens"]))
+    assert react.status_code == 409
+
+    # Erneutes Anonymisieren wird abgelehnt
+    again = await client.post(f"{USERS_URL}/{user_id}/anonymize", headers=auth(registered_user["tokens"]))
+    assert again.status_code == 409
+
+
+async def test_cannot_anonymize_self(client: AsyncClient, registered_user):
+    user_id = registered_user["user"]["id"]
+    resp = await client.post(f"{USERS_URL}/{user_id}/anonymize", headers=auth(registered_user["tokens"]))
+    assert resp.status_code == 400
diff --git a/frontend/src/pages/UsersPage.tsx b/frontend/src/pages/UsersPage.tsx
index a52d4c4..66d7518 100644
--- a/frontend/src/pages/UsersPage.tsx
+++ b/frontend/src/pages/UsersPage.tsx
@@ -20,6 +20,7 @@ interface UserOut {
   can_manual_time_entry: boolean
   entry_date: string | null
   exit_date: string | null
+  anonymized_at: string | null
   last_login: string | null
   created_at: string
 }
@@ -221,6 +222,21 @@ export function UsersPage() {
     }
   }
 
+  async function handleAnonymize(user: UserOut) {
+    if (!confirm(
+      `DSGVO-Anonymisierung von ${user.full_name}?\n\n` +
+      `Name und E-Mail werden unwiderruflich entfernt, das Konto wird deaktiviert. ` +
+      `Zeit-, Abwesenheits- und Auszahlungsdaten bleiben (gesetzliche Aufbewahrung), ` +
+      `aber ohne Personenbezug. Nicht umkehrbar.`
+    )) return
+    try {
+      await api.post(`/users/${user.id}/anonymize`, {})
+      load()
+    } catch (e: unknown) {
+      alert(e instanceof Error ? e.message : 'Fehler')
+    }
+  }
+
   async function handleEditRole() {
     if (!editUser) return
     setEditLoading(true)
@@ -415,14 +431,19 @@ export function UsersPage() {
                     </td>
                     <td className='px-4 py-3'>
                       <Badge
-                        text={u.is_active ? 'Aktiv' : 'Inaktiv'}
-                        color={u.is_active ? 'bg-green-100 text-green-700' : 'bg-red-100 text-red-600'}
+                        text={u.anonymized_at ? 'Anonymisiert' : u.is_active ? 'Aktiv' : 'Inaktiv'}
+                        color={u.anonymized_at ? 'bg-gray-200 text-gray-500' : u.is_active ? 'bg-green-100 text-green-700' : 'bg-red-100 text-red-600'}
                       />
                     </td>
                     <td className='px-4 py-3 text-gray-500'>
                       {u.last_login ? new Date(u.last_login).toLocaleDateString('de-DE') : '—'}
                     </td>
                     <td className='px-4 py-3'>
+                      {u.anonymized_at ? (
+                        <div className='flex justify-end text-xs text-gray-400 italic'>
+                          anonymisiert am {new Date(u.anonymized_at).toLocaleDateString('de-DE')}
+                        </div>
+                      ) : (
                       <div className='flex gap-2 justify-end'>
                         <button
                           onClick={() => {
@@ -450,7 +471,15 @@ export function UsersPage() {
                             Reaktivieren
                           </button>
                         )}
+                        <button
+                          onClick={() => handleAnonymize(u)}
+                          className='text-xs text-gray-400 hover:text-red-600 hover:underline'
+                          title='DSGVO Art. 17 – Personenbezug entfernen (nicht umkehrbar)'
+                        >
+                          Anonymisieren
+                        </button>
                       </div>
+                      )}
                     </td>
                   </tr>
                 ))}