diff --git a/stdlib/3/unittest/mock.pyi b/stdlib/3/unittest/mock.pyi
index 84fe40e45..d082a52fd 100644
--- a/stdlib/3/unittest/mock.pyi
+++ b/stdlib/3/unittest/mock.pyi
@@ -63,7 +63,7 @@ if sys.version_info >= (3, 3):
         def __call__(_mock_self, *args: Any, **kwargs: Any) -> Any: ...
 
     class Mock(CallableMixin, NonCallableMock):
-        def __init__(self) -> None: ...
+        def __init__(self, spec: Any = ..., spec_set: Any = ..., side_effect: Any = ..., return_value: Any = ..., wraps: Any = ..., name: Any = ..., **kwargs: Any) -> None: ...
 
     class _patch:
         attribute_name = ...  # type: Any