diff --git a/.travis.yml b/.travis.yml
index 8b2e0ffe..81eb5690 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,12 @@
 language: r
 cache: packages
 
+addons:
+  apt:
+    packages:
+    - tcl8.5-dev
+    - tk8.5-dev
+
 notifications:
   email:
     on_success: change