diff --git a/scripts/imgtool/main.py b/scripts/imgtool/main.py
index 674063a..6188e78 100755
--- a/scripts/imgtool/main.py
+++ b/scripts/imgtool/main.py
@@ -3,6 +3,8 @@
 # Copyright 2017-2020 Linaro Limited
 # Copyright 2019-2020 Arm Limited
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at