diff --git a/website/source/docs/builders/openstack.html.markdown b/website/source/docs/builders/openstack.html.markdown
index 20684111b..441f8a7c9 100644
--- a/website/source/docs/builders/openstack.html.markdown
+++ b/website/source/docs/builders/openstack.html.markdown
@@ -51,6 +51,9 @@ Required:
 
 Optional:
 
+* `project` (string) - The project name to boot the instance into. Some
+  OpenStack installations require this. By default this is empty.
+
 * `ssh_port` (int) - The port that SSH will be available on. Defaults to port
   22.