diff --git a/tox.ini b/tox.ini
index c3c2f2a..d1ddb32 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,12 +20,15 @@ deps =
 commands = python manage.py test {posargs} --settings=masakaridashboard.test.settings --ignore-files=masakaridashboard/test/uuidsentinel.py
 
 [testenv:pep8]
+basepython = python3
 commands = flake8 {posargs}
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 commands =
   coverage erase
   coverage run {toxinidir}/manage.py test masakaridashboard --settings=masakaridashboard.test.settings {posargs} --exclude-dir=masakaridashboard/test/integration_tests {posargs}
@@ -39,6 +42,7 @@ commands =
     python manage.py test {posargs} --settings=masakaridashboard.test.settings --ignore-files=masakaridashboard/test/uuidsentinel.py
 
 [testenv:eslint]
+basepython = python3
 whitelist_externals = npm
 commands =
   npm install
@@ -46,6 +50,7 @@ commands =
   npm run lint
 
 [testenv:karma]
+basepython = python3
 # NOTE(shu-mutou): Until PhantomJS setup get reliable, we use
 # Chromium for JS test. And npm can't launch Chromium via tox.
 #whitelist_externals = npm
@@ -59,6 +64,7 @@ commands =
   echo "nexecute `npm run test`"
 
 [testenv:docs]
+basepython = python3
 # We need to install horizon dependencies to build module references
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
@@ -68,6 +74,7 @@ commands =
   sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
+basepython = python3
 # There is no need to install horizon.
 usedevelop = False
 deps =