diff --git a/tox.ini b/tox.ini
index fd12ce5..69ecb3a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,9 +13,11 @@ commands = python setup.py testr --slowest --testr-args='{posargs}'
 whitelist_externals = find
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 commands =
     find . -type f -name "*.pyc" -delete
     python setup.py build_sphinx