diff --git a/tox.ini b/tox.ini
index be8dd2dcd..6c5e6b898 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,6 +18,7 @@ deps =
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [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
@@ -26,6 +27,7 @@ deps = bindep
 commands = bindep test
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:venv]
@@ -33,18 +35,21 @@ commands = {posargs}
 passenv = *
 
 [testenv:cover]
+basepython = python3
 commands =
     python setup.py testr --coverage --testr-args='{posargs}'
     coverage combine
     coverage report -m
 
 [testenv:debug]
+basepython = python3
 deps =
     oslotest
     {[testenv]deps}
 commands = oslo_debug_helper -t tripleoclient/tests {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
@@ -58,6 +63,7 @@ builtins = _
 exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build,releasenotes
 
 [testenv:genconfig]
+basepython = python3
 setenv =
    HOME={env:HOME:/home/stack}
 commands =
@@ -65,6 +71,7 @@ commands =
    oslo-config-generator --config-file config-generator/standalone.conf
 
 [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