diff --git a/tox.ini b/tox.ini
index e9a28fe..171b0a0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,14 +8,16 @@ deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:pep8]
-basepython = python2.7
+basepython = python3
 commands =
     doc8 README.rst doc/source specs
 
 [testenv:docs]
+basepython = python3
 # TODO(milan): remove the version pin once feedformatter supports python3
 basepython = python2.7
 commands = python setup.py build_sphinx