diff --git a/tox.ini b/tox.ini
index f93f347..ffe1237 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py34,py27,pep8
+envlist = py35,py27,pep8
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
@@ -9,6 +9,7 @@ deps = -r{toxinidir}/requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
            flake8 --filename=cfn-* bin
 
@@ -19,10 +20,12 @@ deps = -r{toxinidir}/requirements.txt
 commands = bash tools/lintstack.sh
 
 [testenv:cover]
+basepython = python3
 commands =
   python setup.py testr --coverage --testr-args='{posargs}'
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [flake8]
@@ -30,6 +33,7 @@ show-source = true
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,tools
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html