diff --git a/git_config.py b/git_config.py
index 4f053ed05..1bde4795c 100644
--- a/git_config.py
+++ b/git_config.py
@@ -180,7 +180,7 @@ def DumpConfigDict(self):
             config_dict[key] = self.GetString(key)
         return config_dict
 
-    def GetBoolean(self, name: str) -> Union[str, None]:
+    def GetBoolean(self, name: str) -> Union[bool, None]:
         """Returns a boolean from the configuration file.
 
         Returns: