diff --git a/.travis.yml b/.travis.yml
index e57b0af7..86a622ed 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,6 +27,7 @@ env:
     - RACKET_VERSION=6.3
     - RACKET_VERSION=6.4
     - RACKET_VERSION=6.5
+    - RACKET_VERSION=6.6
     - RACKET_VERSION=HEAD
 
 matrix: