diff --git a/README.rst b/README.rst
index a73c71c77e58499277ba23542767c2282864c86d..afd4bbc4d072cdf9bb757a8255cb0b91ef5ee91b 100644
--- a/README.rst
+++ b/README.rst
@@ -808,7 +808,7 @@ directory of your choice::
 Synapse has a number of external dependencies, that are easiest
 to install using pip and a virtualenv::
 
-    virtualenv env
+    virtualenv -p python2.7 env
     source env/bin/activate
     python synapse/python_dependencies.py | xargs pip install
     pip install lxml mock