diff --git a/tox.ini b/tox.ini
index 6533406..52fe139 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
 minversion = 2.0
 skipsdist = True
-envlist = py27,pep8,cover
+envlist = py27,py35,pep8,cover
 
 [testenv]
 usedevelop = True
@@ -20,6 +20,7 @@ commands =
     nosetests -w test
 
 [testenv:cover]
+basepython = python3
 commands = nosetests -w test --cover-package monasca_analytics
 setenv = VIRTUAL_ENV={envdir}
          NOSE_WITH_COVERAGE=1
@@ -38,6 +39,7 @@ commands =
 [testenv:docs]
 
 [testenv:venv]
+basepython = python3
 install_command = pip install -U {opts} {packages}
 commands = {posargs}