diff --git a/activemodel/lib/active_model/attribute.rb b/activemodel/lib/active_model/attribute.rb
index b75ff80b31..0b669db58a 100644
--- a/activemodel/lib/active_model/attribute.rb
+++ b/activemodel/lib/active_model/attribute.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "active_support/core_ext/object/duplicable"
+require "active_model/type"
 
 module ActiveModel
   class Attribute # :nodoc: