diff --git a/.travis.yml b/.travis.yml
index 09182c86..3a54ed0a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,25 @@
 language: python
-# command to install tox, tox env will install deps.
-install: pip install tox
-# command to run tests
-script: tox
+
+matrix:
+  include:
+    # latest python and system-provided python versions
+    - python: 3.6
+      env: TOX_ENV=py26,py27,py33,py34,py36,pypy
+    # extra python versions that need downloading
+    - python: 3.5
+      env: TOX_ENV=py35
+    - python: pypy3
+      env: TOX_ENV=pypy3
+
+sudo: false
+
+install:
+  - pip install tox
+  - pip install python-coveralls
+
+script: tox -e ${TOX_ENV}
 
 after_success:
-    coveralls
+  - coveralls
 
+cache: pip
diff --git a/requirements.txt b/requirements.txt
index 4f5aad47..7a803b02 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,4 +5,4 @@ python-dateutil>=2.2
 pymongo>=2.7.1
 tox>=1.9
 mock>=1.0.1
-Sphinx>=1.1.3
+Sphinx>=1.1.3,<=1.5
diff --git a/tox.ini b/tox.ini
index 5cf4e8ff..481da6c6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,16 +1,18 @@
 [tox]
-distshare={homedir}/.tox/distshare
-envlist=py26,py27,py33,py34
-indexserver=
-    pypi = https://pypi.python.org/simple
+envlist = py26, py27, py33, py34, py35, py36, pypy, pypy3
 
 [testenv]
-commands= coverage run --source schematics -m py.test
-          coverage report
-setenv =
-       PYTHONDONTWRITEBYTECODE=1
 deps = -r{toxinidir}/requirements.txt
+commands = py.test
+
+[testenv:py34]
+commands = coverage run --source=schematics -m py.test
+           coverage report
 
 [pytest]
-addopts=tests
-pep8maxlinelength=120
+testpaths = tests
+pep8maxlinelength = 115
+
+[flake8]
+max-line-length = 115
+ignore = E203, E221, E261, W391