diff --git a/tox.ini b/tox.ini
index baa5dd7..97fbdd0 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}
@@ -20,6 +19,7 @@ commands =
 basepython = python2.7
 
 [testenv:pep8]
+basepython = python3
 deps =
   -r{toxinidir}/test-requirements.txt
 commands =
@@ -28,6 +28,7 @@ commands =
   bandit -r oslo_rootwrap tests -n5 --skip B404
 
 [testenv:cover]
+basepython = python3
 deps = {[testenv]deps}
     coverage
 commands =
@@ -35,9 +36,11 @@ commands =
 
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
@@ -50,13 +53,16 @@ basepython = python2.7
 commands = python benchmark/benchmark.py
 
 [testenv:benchmark3]
+basepython = python3
 commands = python3 benchmark/benchmark.py
 
 [testenv:releasenotes]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:lower-constraints]
+basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt