diff --git a/.travis.yml b/.travis.yml
index 314288be19e7b0b14de1083a21e7ad3811035922..e0647ebbd95909f40e5acc213e15556b9167dd4d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,6 +6,7 @@ install:
   - gem install rdiscount
   - gem install json
   - gem install parallel
+  - gem install execjs
   - gem install therubyracer -v 0.10.1
   - gem install rspec
   - gem install rake