diff --git a/tox.ini b/tox.ini
index a77e898b..4680a6ee 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,6 +21,7 @@ deps =
   -r{toxinidir}/requirements.txt
 
 [testenv:pep8]
+basepython = python3
 deps =
   -r{toxinidir}/test-requirements.txt
   flake8
@@ -30,6 +31,7 @@ commands =
   bandit -c bandit.yaml -r cliff -x tests -n5
 
 [testenv:venv]
+basepython = python3
 # TODO(modred) remove doc/requirements.txt once the openstack-build-sphinx-docs
 # job is updated.
 deps =
@@ -48,6 +50,7 @@ deps = os:openstack/python-openstackclient:python-openstackclient
 commands = {toxinidir}/integration-tests/openstackclient-tip.sh {envdir}
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -b html doc/source doc/build/html