diff --git a/stdlib/3/types.pyi b/stdlib/3/types.pyi
index 8221d8d82..73e28a5e9 100644
--- a/stdlib/3/types.pyi
+++ b/stdlib/3/types.pyi
@@ -77,6 +77,7 @@ class MappingProxyType(Mapping[_KT, _VT], Generic[_KT, _VT]):
     def __getitem__(self, k: _KT) -> _VT: ...
     def __iter__(self) -> Iterator[_KT]: ...
     def __len__(self) -> int: ...
+    def copy(self) -> Mapping[_KT, _VT]: ...
 
 class SimpleNamespace:
     def __init__(self, **kwargs: Any) -> None: ...