diff --git a/tox.ini b/tox.ini
index 7983cb45..f1db2f1e 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}
 whitelist_externals = bash
                       env
@@ -26,6 +25,7 @@ commands =
 passenv = OS_TEST_DBAPI_ADMIN_CONNECTION
 
 [testenv:sqla_09]
+basepython = python3
 commands = pip install SQLAlchemy>=0.9.0,!=0.9.5,<1.0.0
             python setup.py testr --slowest --testr-args='{posargs}'
 
@@ -36,24 +36,29 @@ commands =
     env TEST_EVENTLET=1 bash tools/pretty_tox.sh '{posargs}'
 
 [testenv:pep8]
+basepython = python3
 commands =
   flake8
   # Run security linter
   bandit -r oslo_db -x tests -n5 --skip B105,B311
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 commands = python setup.py test --coverage --coverage-package-name=oslo_db --testr-args='{posargs}'
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands =
     doc8 -e .rst CONTRIBUTING.rst HACKING.rst README.rst doc/source
     sphinx-build -b html doc/source doc/build/html
 
 [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
 
@@ -68,6 +73,7 @@ import_exceptions =
   oslo_db._i18n
 
 [testenv:lower-constraints]
+basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt