diff --git a/gui/scyther-gui.py b/gui/scyther-gui.py
index 2108baf..2c36c03 100755
--- a/gui/scyther-gui.py
+++ b/gui/scyther-gui.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 """
 	Scyther : An automatic verifier for security protocols.
 	Copyright (C) 2007-2013 Cas Cremers