diff --git a/src/stubgen.py b/src/stubgen.py
index 9098c50e..633e7dd3 100755
--- a/src/stubgen.py
+++ b/src/stubgen.py
@@ -683,7 +683,7 @@ def is_valid_module(module_name: str) -> bool:
             if mod_name == "builtins":
                 # Simplify builtins
                 return cls_name if cls_name != "NoneType" else "None"
-            if full_name.startswith(self.module.__name__):
+            if full_name.startswith(self.module.__name__ + "."):
                 # Strip away the module prefix for local classes
                 return full_name[len(self.module.__name__) + 1 :]
             elif mod_name == "typing" or mod_name == "collections.abc":