diff --git a/activemodel/lib/active_model/serialization.rb b/activemodel/lib/active_model/serialization.rb
index 3751e4a741dd2..6d8fd21814768 100644
--- a/activemodel/lib/active_model/serialization.rb
+++ b/activemodel/lib/active_model/serialization.rb
@@ -74,7 +74,7 @@ module Serialization
     def serializable_hash(options = nil)
       options ||= {}
 
-      attribute_names = attributes.keys.sort
+      attribute_names = attributes.keys
       if only = options[:only]
         attribute_names &= Array(only).map(&:to_s)
       elsif except = options[:except]