diff --git a/tox.ini b/tox.ini
index 07cbc38..a108d7d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,17 +13,20 @@ usedevelop = True
 commands = stestr run {posargs}
 
 [testenv:venv]
+basepython = python3
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands = {posargs}
 
 [testenv:pep8]
+basepython = python3
 deps = hacking
 usedevelop = False
 commands =
     flake8
 
 [testenv:cover]
+basepython = python3
 setenv = PYTHON=coverage run --source microversion_parse --parallel-mode
 commands =
     coverage erase
@@ -35,6 +38,7 @@ whitelist_externals =
     find
 
 [testenv:docs]
+basepython = python3
 commands =
     rm -rf doc/build
     python setup.py build_sphinx