diff --git a/tox.ini b/tox.ini
index df038246..c60a937f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,13 +15,16 @@ commands = ostestr {posargs}
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY OS_*
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 passenv = OS_*
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:pep8]
+basepython = python3
 commands =
     flake8 {posargs}