diff --git a/.travis.yml b/.travis.yml
index d88bd60033..18ea8ebd52 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@ language: php
 php:
     - 5.3
     - 5.4
+    - 5.5
 
 env:
     - WP_VERSION=latest WP_MULTISITE=0