diff --git a/tox.ini b/tox.ini
index b4dfa8f44..2214780a0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,12 +23,15 @@ commands =
   # mode. To do this define the TRACE_FAILONLY environmental variable.
 
 [testenv:pep8]
+basepython = python3
 commands = flake8 {posargs}
 
 [testenv:bandit]
+basepython = python3
 commands = bandit -r novaclient -n5 -x tests
 
 [testenv:venv]
+basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
   -r{toxinidir}/test-requirements.txt
@@ -37,6 +40,7 @@ deps =
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
   -r{toxinidir}/requirements.txt
@@ -45,6 +49,7 @@ commands =
   sphinx-build -b html doc/source doc/build/html
 
 [testenv:releasenotes]
+basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
   -r{toxinidir}/requirements.txt
@@ -71,6 +76,7 @@ commands =
   python novaclient/tests/functional/hooks/check_resources.py
 
 [testenv:cover]
+basepython = python3
 commands =
   python setup.py testr --coverage --testr-args='{posargs}'
   coverage report
@@ -92,6 +98,7 @@ exclude=.venv,.git,.tox,dist,*lib/python*,*egg,build,doc/source/conf.py,releasen
 import_exceptions = novaclient.i18n
 
 [testenv:bindep]
+basepython = python3
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system
 # dependencies are missing! This also means that bindep must be installed