diff --git a/tox.ini b/tox.ini
index 3771603..5ffaf57 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,15 +16,19 @@ commands =
  python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:cover]
+basepython = python3
 commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html