diff --git a/actionpack/lib/abstract_controller/railties/routes_helpers.rb b/actionpack/lib/abstract_controller/railties/routes_helpers.rb
index b6e5631a4e..fbd93705ed 100644
--- a/actionpack/lib/abstract_controller/railties/routes_helpers.rb
+++ b/actionpack/lib/abstract_controller/railties/routes_helpers.rb
@@ -7,7 +7,7 @@ module AbstractController
         Module.new do
           define_method(:inherited) do |klass|
             super(klass)
-            if namespace = klass.parents.detect { |m| m.respond_to?(:railtie_routes_url_helpers) }
+            if namespace = klass.module_parents.detect { |m| m.respond_to?(:railtie_routes_url_helpers) }
               klass.include(namespace.railtie_routes_url_helpers(include_path_helpers))
             else
               klass.include(routes.url_helpers(include_path_helpers))