diff --git a/stdlib/datetime.pyi b/stdlib/datetime.pyi
index e82b26923..4426a9eee 100644
--- a/stdlib/datetime.pyi
+++ b/stdlib/datetime.pyi
@@ -179,6 +179,7 @@ class timedelta(SupportsAbs[timedelta]):
     def __lt__(self, other: timedelta) -> bool: ...
     def __ge__(self, other: timedelta) -> bool: ...
     def __gt__(self, other: timedelta) -> bool: ...
+    def __bool__(self) -> bool: ...
     def __hash__(self) -> int: ...
 
 class datetime(date):