diff --git a/stdlib/optparse.pyi b/stdlib/optparse.pyi
index 3474648617c2..a179c2d1bb3c 100644
--- a/stdlib/optparse.pyi
+++ b/stdlib/optparse.pyi
@@ -151,7 +151,7 @@ class OptionContainer:
     def _create_option_mappings(self) -> None: ...
     def _share_option_mappings(self, parser: OptionParser) -> None: ...
     @overload
-    def add_option(self, opt: Option) -> Option: ...
+    def add_option(self, opt: Option, /) -> Option: ...
     @overload
     def add_option(self, arg: str, /, *args: str | None, **kwargs) -> Option: ...
     def add_options(self, option_list: Iterable[Option]) -> None: ...