diff --git a/.travis.yml b/.travis.yml
index 542e314..2ba2976 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@ cache: packages
 
 r_packages:
   - covr
+  - PMCMRplus
 
 after_success:
   - Rscript -e 'covr::codecov()'