diff --git a/tox.ini b/tox.ini
index d16e0f4..0c07ec3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,7 +10,9 @@ setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/test-requirements.txt
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx