diff --git a/tox.ini b/tox.ini
index 7490e90..6211c66 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,9 +1,11 @@
 [tox]
-minversion = 2.0
-envlist = py35,py27,pep8
+minversion = 3.1.1
+envlist = py37,pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 install_command = pip install {opts} {packages}
 deps =
@@ -31,12 +33,10 @@
           OS_STDOUT_CAPTURE
 
 [testenv:pep8]
-basepython = python3
 commands = sh tools/pretty_flake8.sh
 
 
 [testenv:docs]
-basepython = python3
 commands = rm -rf doc/build
            sphinx-build -E -W -b html doc/source doc/build/html
 
@@ -67,7 +67,6 @@
 commands=pip-missing-reqs -d --ignore-file=designate/tests/* designate
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [flake8]