diff --git a/lib/kaminari/models/active_record_extension.rb b/lib/kaminari/models/active_record_extension.rb
index <HASH>..<HASH> 100644
--- a/lib/kaminari/models/active_record_extension.rb
+++ b/lib/kaminari/models/active_record_extension.rb
@@ -18,7 +18,7 @@ module Kaminari
             include Kaminari::ActiveRecordRelationMethods
             include Kaminari::PageScopeMethods
           end
-        end
+        end if kls.superclass == ActiveRecord::Base
       end
     end
   end
Only add extensions to direct descendents of ActiveRecord::Base