diff --git a/tox.ini b/tox.ini
index 5a2eb76dd..9d03fe96f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -43,9 +43,11 @@ commands =
   pip check
 
 [testenv:pep8]
+basepython = python3
 commands = flake8 {posargs}
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:py27]
@@ -64,9 +66,11 @@ 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]