diff --git a/tox.ini b/tox.ini
index 33f83a57..2fcaa593 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,9 +16,11 @@ commands =
   python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:spelling]