diff --git a/activesupport/lib/active_support/core_ext/module/deprecation.rb b/activesupport/lib/active_support/core_ext/module/deprecation.rb
index 5a5b4e3f80..9c169a2598 100644
--- a/activesupport/lib/active_support/core_ext/module/deprecation.rb
+++ b/activesupport/lib/active_support/core_ext/module/deprecation.rb
@@ -1,3 +1,5 @@
+require 'active_support/deprecation'
+
 class Module
   # Declare that a method has been deprecated.
   #   deprecate :foo