diff --git a/stdlib/2/__builtin__.pyi b/stdlib/2/__builtin__.pyi
index 62052cfb7186..85b681a522c4 100644
--- a/stdlib/2/__builtin__.pyi
+++ b/stdlib/2/__builtin__.pyi
@@ -1189,7 +1189,9 @@ else:
 @overload
 def iter(__iterable: Iterable[_T]) -> Iterator[_T]: ...
 @overload
-def iter(__function: Callable[[], _T], __sentinel: _T) -> Iterator[_T]: ...
+def iter(__function: Callable[[], Optional[_T]], __sentinel: None) -> Iterator[_T]: ...
+@overload
+def iter(__function: Callable[[], Any], __sentinel: Any) -> Iterator[Any]: ...
 def isinstance(__o: object, __t: Union[type, Tuple[Union[type, Tuple[Any, ...]], ...]]) -> bool: ...
 def issubclass(__cls: type, __classinfo: Union[type, Tuple[Union[type, Tuple[Any, ...]], ...]]) -> bool: ...
 def len(__o: Sized) -> int: ...
diff --git a/stdlib/2and3/builtins.pyi b/stdlib/2and3/builtins.pyi
index 62052cfb7186..85b681a522c4 100644
--- a/stdlib/2and3/builtins.pyi
+++ b/stdlib/2and3/builtins.pyi
@@ -1189,7 +1189,9 @@ else:
 @overload
 def iter(__iterable: Iterable[_T]) -> Iterator[_T]: ...
 @overload
-def iter(__function: Callable[[], _T], __sentinel: _T) -> Iterator[_T]: ...
+def iter(__function: Callable[[], Optional[_T]], __sentinel: None) -> Iterator[_T]: ...
+@overload
+def iter(__function: Callable[[], Any], __sentinel: Any) -> Iterator[Any]: ...
 def isinstance(__o: object, __t: Union[type, Tuple[Union[type, Tuple[Any, ...]], ...]]) -> bool: ...
 def issubclass(__cls: type, __classinfo: Union[type, Tuple[Union[type, Tuple[Any, ...]], ...]]) -> bool: ...
 def len(__o: Sized) -> int: ...