diff --git a/tools/reorder_message_file.py b/tools/reorder_message_file.py
old mode 100644
new mode 100755
index 368282dd13..8434de8a24
--- a/tools/reorder_message_file.py
+++ b/tools/reorder_message_file.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 # Copyright (C) 2011-2024 Internet Systems Consortium, Inc. ("ISC")
 #
 # This Source Code Form is subject to the terms of the Mozilla Public