diff --git a/activemodel/lib/active_model/validations/helper_methods.rb b/activemodel/lib/active_model/validations/helper_methods.rb
index 5a22b699d8..2176115334 100644
--- a/activemodel/lib/active_model/validations/helper_methods.rb
+++ b/activemodel/lib/active_model/validations/helper_methods.rb
@@ -1,6 +1,6 @@
 module ActiveModel
   module Validations
-    module HelperMethods
+    module HelperMethods # :nodoc:
       private
         def _merge_attributes(attr_names)
           options = attr_names.extract_options!.symbolize_keys