diff --git a/tox.ini b/tox.ini
index f5ee97838..721c4b7a5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,19 +29,23 @@ whitelist_externals = bash
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 
 [testenv:debug]
+basepython = python3
 commands =
   find . -type f -name "*.pyc" -delete
   oslo_debug_helper {posargs}
 
 [testenv:pep8]
+basepython = python3
 commands = flake8 {posargs}
 
 [testenv:fast8]
+basepython = python3
 envdir = {toxworkdir}/pep8
 commands =
     {toxinidir}/tools/fast8.sh
 
 [testenv:pylint]
+basepython = python3
 deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
        -r{toxinidir}/requirements.txt
@@ -49,9 +53,11 @@ deps =
 commands = bash tools/lintstack.sh
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 # To see the report of missing coverage add to commands
 #   coverage report --show-missing
 setenv =
@@ -64,9 +70,11 @@ commands =
     coverage xml -o cover/coverage/xml
 
 [testenv:docs]
+basepython = python3
 commands = 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
 
 [flake8]
@@ -85,6 +93,7 @@ max-complexity=30
 import_exceptions = os_brick.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