diff --git a/.travis.yml b/.travis.yml
index dade59a..a6ab0c5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ jobs:
 before_install:
   - sudo apt-get update -qq
   - sudo apt-get install -qq libarchive-dev
-  - pyenv shell $PYTHON
+  - pyenv shell $TRAVIS_PYTHON_VERSION
 install:
   - make build
 script: