cd9dfda86e72dfa460869614ae06dc3109da63c0
diff --git a/gi/types.py b/gi/types.py
index 58b0043..78b126d 100644
--- a/gi/types.py
+++ b/gi/types.py
@@ -104,7 +104,7 @@ class MetaClassHelper(object):
                             'the method do_%s()' % (base.__info__.get_namespace(),
                                                     base.__info__.get_name(),
                                                     vfunc_info.get_name()))
-                else:
+                elif vfunc is not None:
                     hook_up_vfunc_implementation(vfunc_info, cls.__gtype__,
                                                  vfunc)
 
