diff --git a/fastapi_users/authentication/backend.py b/fastapi_users/authentication/backend.py
index 09861210..b02ca98d 100644
--- a/fastapi_users/authentication/backend.py
+++ b/fastapi_users/authentication/backend.py
@@ -14,7 +14,7 @@ from fastapi_users.authentication.transport import (
 from fastapi_users.types import DependencyCallable
 
 
-class AuthenticationBackend(Generic[models.UP]):
+class AuthenticationBackend(Generic[models.UP, models.ID]):
     """
     Combination of an authentication transport and strategy.