diff --git a/.travis.yml b/.travis.yml
index d8e16fb94b..8067d2ff59 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -56,6 +56,6 @@ script:
 
 # deploy to xran after integration tests
 after_success:
-  - "[ $TARGET = travis ] && Rscript -e covr::codecov() || true"
+  - "[ $TARGET = travis ] && Rscript -e 'covr::codecov()' || true"
   - export R_PKG="$(basename $TRAVIS_REPO_SLUG)"
   - "[ $TARGET = integration ] && (curl https://xran.yihui.name/r-xran | bash)"