diff --git a/tox.ini b/tox.ini
index d7276ea..7ddb710 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,14 +13,17 @@ deps = -r{toxinidir}/requirements.txt
 whitelist_externals = echo
 
 [testenv:pep8]
+basepython = python3
 commands =
   flake8
   doc8 --ignore D001 specs/
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 whitelist_externals = rm
 commands =
   rm -rf doc/build