diff --git a/middleman-core/lib/middleman-core/meta_pages/sitemap_resource.rb b/middleman-core/lib/middleman-core/meta_pages/sitemap_resource.rb
index dcc1a798..9f7be06d 100644
--- a/middleman-core/lib/middleman-core/meta_pages/sitemap_resource.rb
+++ b/middleman-core/lib/middleman-core/meta_pages/sitemap_resource.rb
@@ -1,3 +1,5 @@
+require 'padrino-helpers'
+
 module Middleman
   module MetaPages
     # View class for a sitemap resource