diff --git a/app/routes/users.py b/app/routes/users.py
index ec8e902..bbcd792 100644
--- a/app/routes/users.py
+++ b/app/routes/users.py
@@ -18,6 +18,22 @@ from app.services.user_service import user_service
 router = APIRouter(prefix="/api/v1/users", tags=["users"])
 
 
+def _parse_role_id(raw: str | None) -> uuid.UUID | None:
+    """Convert a string body value into a UUID or None.
+
+    Empty string and None are both treated as "no role_id".
+    """
+    if raw is None or raw == "":
+        return None
+    try:
+        return uuid.UUID(raw)
+    except (ValueError, AttributeError):
+        raise HTTPException(
+            400,
+            detail={"detail": "Invalid role_id", "code": "invalid_role_id"},
+        ) from None
+
+
 @router.get("")
 async def list_users(
     page: int = Query(1, ge=1),
@@ -40,6 +56,7 @@ async def create_user(
     """Create a new user (admin only)."""
     tenant_id = uuid.UUID(current_user["tenant_id"])
     user_id = uuid.UUID(current_user["user_id"])
+    role_id = _parse_role_id(body.role_id)
 
     user = await user_service.create_user(
         db,
@@ -48,6 +65,7 @@ async def create_user(
         body.name,
         body.password,
         body.role,
+        role_id,
         body.is_active,
     )
 
@@ -59,7 +77,7 @@ async def create_user(
         "create",
         "user",
         user.id,
-        changes={"email": body.email, "name": body.name, "role": body.role},
+        changes={"email": body.email, "name": body.name, "role": body.role, "role_id": body.role_id},
     )
 
     # Notification
@@ -77,6 +95,7 @@ async def create_user(
         "email": user.email,
         "name": user.name,
         "role": user.role,
+        "role_id": str(user.role_id) if user.role_id else None,
         "is_active": user.is_active,
         "tenant_id": str(user.tenant_id),
     }
@@ -106,6 +125,7 @@ async def get_user(
         "email": user.email,
         "name": user.name,
         "role": user.role,
+        "role_id": str(user.role_id) if user.role_id else None,
         "is_active": user.is_active,
         "tenant_id": str(user.tenant_id),
     }
@@ -133,15 +153,20 @@ async def update_user(
         changes["name"] = body.name
     if body.role is not None:
         changes["role"] = body.role
+    if body.role_id is not None:
+        changes["role_id"] = body.role_id
     if body.is_active is not None:
         changes["is_active"] = body.is_active
 
+    role_id = _parse_role_id(body.role_id)
+
     user = await user_service.update_user(
         db,
         tenant_id,
         uid,
         body.name,
         body.role,
+        role_id,
         body.is_active,
     )
     if user is None:
@@ -154,6 +179,7 @@ async def update_user(
         "email": user.email,
         "name": user.name,
         "role": user.role,
+        "role_id": str(user.role_id) if user.role_id else None,
         "is_active": user.is_active,
         "tenant_id": str(user.tenant_id),
     }