diff --git a/tox.ini b/tox.ini
index 44fa5a9..3e110d9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,6 @@ minversion = 2.0
 envlist = py35,py27,pep8
 
 [testenv]
-basepython = python3
 install_command = pip install {opts} {packages}
 deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
@@ -16,15 +15,19 @@ commands =
 basepython = python2.7
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 commands =
   python setup.py testr --coverage
 
@@ -34,6 +37,7 @@ ignore = E721
 exclude=.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg
 
 [testenv:lower-constraints]
+basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt