diff --git a/stdlib/3/functools.pyi b/stdlib/3/functools.pyi
index 7db91aaf5..7c0c0d7bb 100644
--- a/stdlib/3/functools.pyi
+++ b/stdlib/3/functools.pyi
@@ -12,10 +12,10 @@ _T = TypeVar("_T")
 _S = TypeVar("_S")
 @overload
 def reduce(function: Callable[[_T, _S], _T],
-           sequence: Iterator[_S], initial: _T) -> _T: ...
+           sequence: Iterable[_S], initial: _T) -> _T: ...
 @overload
 def reduce(function: Callable[[_T, _T], _T],
-           sequence: Iterator[_T]) -> _T: ...
+           sequence: Iterable[_T]) -> _T: ...
 
 
 class CacheInfo(NamedTuple('CacheInfo', [