diff --git a/smach_ros/test/ref_server.py b/smach_ros/test/ref_server.py
index 94e0330..177c665 100755
--- a/smach_ros/test/ref_server.py
+++ b/smach_ros/test/ref_server.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright (c) 2009, Willow Garage, Inc.
 # All rights reserved.
 #