diff --git a/tox.ini b/tox.ini
index 8c7c843..680beab 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,12 +13,15 @@ deps =
 commands = stestr run --slowest {posargs}
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 setenv =
     PYTHON=coverage run --source $project --parallel-mode
 commands =
@@ -29,6 +32,7 @@ commands =
     coverage report
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [flake8]