diff --git a/lib/active_model_serializers.rb b/lib/active_model_serializers.rb
index 192b414be..15551f4b5 100644
--- a/lib/active_model_serializers.rb
+++ b/lib/active_model_serializers.rb
@@ -2,6 +2,7 @@
 require 'active_support'
 require 'active_support/core_ext/object/with_options'
 require 'active_support/core_ext/string/inflections'
+require 'active_support/json'
 module ActiveModelSerializers
   extend ActiveSupport::Autoload
   autoload :Model
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 66609eaf3..2e9c80f6e 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -14,7 +14,6 @@
 require 'action_controller'
 require 'action_controller/test_case'
 require 'action_controller/railtie'
-require 'active_support/json'
 require 'active_model_serializers'
 require 'fileutils'
 FileUtils.mkdir_p(File.expand_path('../../tmp/cache', __FILE__))