diff --git a/.travis.yml b/.travis.yml
index 16a86d0..1d1bee0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,8 +5,9 @@ python:
   - "3.3"
   - "3.4"
   - "3.5"
+env:
+  - TOXENV=py
 install:
-  - pip install . "Twisted>=15.5.0" pyflakes
+  - pip install tox
 script:
-  - pyflakes src
-  - trial wormhole
+  - tox
diff --git a/README.md b/README.md
index da36095..7acfeed 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,9 @@ and do not need to be memorized.
 On Debian/Ubuntu systems, you may first need `apt-get python-dev libffi-dev`.
 On OS-X, you may need to install `pip`.
 
+Developers can clone the source tree and run `tox` to run the unit tests on
+all supported (and installed) versions of python: 2.7, 3.3, 3.4, and 3.5.
+
 ## Motivation
 
 * Moving a file to a friend's machine, when the humans can speak to each
diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..2208e10
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,22 @@
+# Tox (http://tox.testrun.org/) is a tool for running tests
+# in multiple virtualenvs. This configuration file will run the
+# test suite on all supported python versions. To use it, "pip install tox"
+# and then run "tox" from this directory.
+
+[tox]
+envlist = py27,py33,py34,py35,meta
+skip_missing_interpreters = True
+
+[testenv]
+deps =
+    twisted
+    coverage
+commands =
+    trial {posargs:wormhole}
+
+[testenv:meta]
+deps =
+    pyflakes
+commands =
+    pyflakes setup.py src
+    wormhole --version