diff --git a/jekyll.gemspec b/jekyll.gemspec
index 5e2c4b22..9b003330 100644
--- a/jekyll.gemspec
+++ b/jekyll.gemspec
@@ -45,6 +45,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency('launchy', "~> 2.1.2")
   s.add_development_dependency('simplecov', "~> 0.7")
   s.add_development_dependency('simplecov-gem-adapter', "~> 1.0.1")
+  s.add_development_dependency('activesupport', '~> 3.2.13')
 
   # = MANIFEST =
   s.files = %w[