diff --git a/tox.ini b/tox.ini
index 247b7cc..9312cec 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,28 +16,35 @@ whitelist_externals =
   find
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 commands = python setup.py test --coverage --testr-args='{posargs}'
 
 [testenv:docs]
+basepython = python3
 commands =
   bash -c "rm -rf doc/build"
   bash -c "rm -rf doc/source/api"
   python setup.py build_sphinx
 
 [testenv:releasenotes]
+basepython = python3
 commands =
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:genconfig]
+basepython = python3
 commands = oslo-config-generator --config-file=etc/proton/proton-config-generator.conf
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper {posargs}
 
 [flake8]