diff --git a/tox.ini b/tox.ini
index c179eaac..de6f9ee1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -27,20 +27,25 @@ whitelist_externals = find
 sitepackages = True
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:cover]
+basepython = python3
 setenv = {[testenv]setenv}
          NOSE_WITH_COVERAGE=1
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html