diff --git a/tox.ini b/tox.ini
index b7c6c61..a3e1c66 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,20 +15,25 @@ commands =
     coverage report --show-missing
 
 [testenv:pep8]
+basepython = python3
 commands =
   flake8
   reno -q lint
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 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]