diff --git a/tox.ini b/tox.ini
index 4119c88..137c100 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,9 +26,11 @@ commands =
         watcher_dashboard
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:py3-dj111]
@@ -42,15 +44,19 @@ basepython = python2.7
 commands = /bin/bash run_tests.sh -N --integration --selenium-headless {posargs}
 
 [testenv:releasenotes]
+basepython = python3
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:cover]
+basepython = python3
 commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper {posargs}
 
 [flake8]