diff --git a/tox.ini b/tox.ini
index 2ed825f..dfeef0f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,13 +17,16 @@ commands =
 sitepackages = True
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:cover]
+basepython = python3
 commands =
   python setup.py test --coverage --coverage-package-name=os_collect_config
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [flake8]