diff --git a/.travis.yml b/.travis.yml
index e6b64cb..a806585 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,6 +18,7 @@ before_install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install python3 || brew upgrade python3; fi
 
 install:
+  - pip3 install --upgrade six
   - pip3 install --upgrade --editable .[test,md5,bcrypt]
 
 script: