diff --git a/tox.ini b/tox.ini
index 38f78bdc..527a6a74 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,6 +11,7 @@ setenv =
 deps = -r{toxinidir}/test-requirements.txt
 
 [testenv:docs]
+basepython = python3
 whitelist_externals = rm
 commands =
   rm -fr doc/build
@@ -18,11 +19,13 @@ commands =
   doc8 --ignore D001 doc/source
 
 [testenv:pep8]
+basepython = python3
 commands =
   flake8
   doc8 --ignore D001 specs/
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [flake8]