diff --git a/tox.ini b/tox.ini
index 74f6f956b..ce88af9ed 100644
--- a/tox.ini
+++ b/tox.ini
@@ -36,9 +36,11 @@ commands =
   python -m twine check dist/*
 
 [testenv:pep8]
+basepython = python3
 commands = flake8 {posargs}
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:py27]
@@ -57,9 +59,11 @@ commands = pytest {posargs}
 commands = python setup.py test --coverage --testr-args='{posargs}'
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper {posargs}
 
 [flake8]