diff --git a/lib/jekyll.rb b/lib/jekyll.rb
index 90147ac3..604ff238 100644
--- a/lib/jekyll.rb
+++ b/lib/jekyll.rb
@@ -34,6 +34,7 @@ require 'jekyll/utils'
 require 'jekyll/stevenson'
 require 'jekyll/deprecator'
 require 'jekyll/configuration'
+require 'jekyll/plugin_manager'
 require 'jekyll/site'
 require 'jekyll/convertible'
 require 'jekyll/url'