diff --git a/scim2_models/rfc7643/user.py b/scim2_models/rfc7643/user.py
index d1d2239..9c7dfa2 100644
--- a/scim2_models/rfc7643/user.py
+++ b/scim2_models/rfc7643/user.py
@@ -17,6 +17,7 @@
 from ..base import Returned
 from ..base import Uniqueness
 from ..utils import Base64Bytes
+from .resource import AnyExtension
 from .resource import Resource
 
 
@@ -213,7 +214,7 @@ class X509Certificate(MultiValuedComplexAttribute):
     """The value of an X.509 certificate."""
 
 
-class User(Resource):
+class User(Resource[AnyExtension]):
     schemas: Annotated[list[str], Required.true] = [
         "urn:ietf:params:scim:schemas:core:2.0:User"
     ]
diff --git a/tests/test_list_response.py b/tests/test_list_response.py
index cf9419e..dfa0d5e 100644
--- a/tests/test_list_response.py
+++ b/tests/test_list_response.py
@@ -40,7 +40,7 @@ def test_enterprise_user(load_sample):
     }
     response = ListResponse[User[EnterpriseUser]].model_validate(payload)
     obj = response.resources[0]
-    assert isinstance(obj, User[EnterpriseUser])
+    assert isinstance(obj, User)
 
 
 def test_group(load_sample):