diff --git a/stdlib/typing.pyi b/stdlib/typing.pyi
index 270b9bb56..c4f9819ed 100644
--- a/stdlib/typing.pyi
+++ b/stdlib/typing.pyi
@@ -468,9 +468,13 @@ class MutableMapping(Mapping[_KT, _VT], Generic[_KT, _VT]):
     @overload
     def pop(self, __key: _KT) -> _VT: ...
     @overload
-    def pop(self, __key: _KT, __default: _VT | _T = ...) -> _VT | _T: ...
+    def pop(self, __key: _KT, __default: _VT | _T) -> _VT | _T: ...
     def popitem(self) -> tuple[_KT, _VT]: ...
-    def setdefault(self, __key: _KT, __default: _VT = ...) -> _VT: ...
+    # This overload should be allowed only if the value type is compatible with None.
+    @overload
+    def setdefault(self: MutableMapping[_KT, _T | None], __key: _KT) -> _T | None: ...
+    @overload
+    def setdefault(self, __key: _KT, __default: _VT) -> _VT: ...
     # 'update' used to take a Union, but using overloading is better.
     # The second overloaded type here is a bit too general, because
     # Mapping[Tuple[_KT, _VT], W] is a subclass of Iterable[Tuple[_KT, _VT]],