diff --git a/README.md b/README.md
index c8f8937e..545a1ae5 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ The Gaussian processes framework in Python.
 * GPy [homepage](http://sheffieldml.github.io/GPy/)
 * Tutorial [notebooks](http://nbviewer.ipython.org/github/SheffieldML/notebook/blob/master/GPy/index.ipynb)
 * User [mailing-list](https://lists.shef.ac.uk/sympa/subscribe/gpy-users)
-* Developer [documentation](http://gpy.readthedocs.io/)
+* Developer [documentation](http://gpy.readthedocs.io/) [documentation (devel branch)](https://gpy.readthedocs.io/en/devel/)
 * Travis-CI [unit-tests](https://travis-ci.org/SheffieldML/GPy)
 * [![licence](https://img.shields.io/badge/licence-BSD-blue.svg)](http://opensource.org/licenses/BSD-3-Clause)
   [![Research software impact](http://depsy.org/api/package/pypi/GPy/badge.svg)](http://depsy.org/package/python/GPy)