diff --git a/Gemfile b/Gemfile
index b241cdc33c400..cb8f85b0a318f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ gemspec
 
 gem 'arel', github: 'rails/arel', branch: 'master'
 
-gem 'mocha', github: 'freerange/mocha', require: false
+gem 'mocha', '~> 0.13.0', require: false
 gem 'rack-test', github: 'brynary/rack-test'
 gem 'rack-cache', '~> 1.2'
 gem 'bcrypt-ruby', '~> 3.0.0'
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 24989fc244cb7..2bbc41296f390 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Simplify mocha integration and remove monkey-patches, bumping mocha to 0.13.0. *James Mead*
+
 *   `#as_json` isolates options when encoding a hash.
     Fix #8182