diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 4e038cfd75d1..a55be41d1a5d 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -668,7 +668,7 @@ def _verify_arg_default_value(
 
 
 def maybe_strip_cls(name: str, args: list[nodes.Argument]) -> list[nodes.Argument]:
-    if name in ("__init_subclass__", "__class_getitem__"):
+    if args and name in ("__init_subclass__", "__class_getitem__"):
         # These are implicitly classmethods. If the stub chooses not to have @classmethod, we
         # should remove the cls argument
         if args[0].variable.name == "cls":