diff --git a/podman_compose.py b/podman_compose.py
index 956148e..e41008a 100755
--- a/podman_compose.py
+++ b/podman_compose.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
+# SPDX-License-Identifier: GPL-2.0
 # https://docs.docker.com/compose/compose-file/#service-configuration-reference
 # https://docs.docker.com/samples/
 # https://docs.docker.com/compose/gettingstarted/
diff --git a/pytests/test_can_merge_build.py b/pytests/test_can_merge_build.py
index 600dc42..86a019b 100644
--- a/pytests/test_can_merge_build.py
+++ b/pytests/test_can_merge_build.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 import copy
 import os
 import argparse
diff --git a/pytests/test_can_merge_cmd_ent.py b/pytests/test_can_merge_cmd_ent.py
index 6080945..2a3295d 100644
--- a/pytests/test_can_merge_cmd_ent.py
+++ b/pytests/test_can_merge_cmd_ent.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 import copy
 import os
 import argparse
diff --git a/pytests/test_normalize_final_build.py b/pytests/test_normalize_final_build.py
index 4f0db34..6915bbe 100644
--- a/pytests/test_normalize_final_build.py
+++ b/pytests/test_normalize_final_build.py
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 # pylint: disable=protected-access
 
 import argparse
diff --git a/pytests/test_volumes.py b/pytests/test_volumes.py
index 8107923..4c6a366 100644
--- a/pytests/test_volumes.py
+++ b/pytests/test_volumes.py
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 # pylint: disable=redefined-outer-name
 import unittest
 
diff --git a/setup.py b/setup.py
index f350a03..56082e0 100644
--- a/setup.py
+++ b/setup.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 import os
 from setuptools import setup
 
diff --git a/tests/test_podman_compose.py b/tests/test_podman_compose.py
index ed4dcac..e571805 100644
--- a/tests/test_podman_compose.py
+++ b/tests/test_podman_compose.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 from pathlib import Path
 import subprocess
 import os
diff --git a/tests/test_podman_compose_config.py b/tests/test_podman_compose_config.py
index d04899b..dfeddce 100644
--- a/tests/test_podman_compose_config.py
+++ b/tests/test_podman_compose_config.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 """
 test_podman_compose_config.py
 
diff --git a/tests/test_podman_compose_include.py b/tests/test_podman_compose_include.py
index b40e5ab..c09df32 100644
--- a/tests/test_podman_compose_include.py
+++ b/tests/test_podman_compose_include.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 from pathlib import Path
 import subprocess
 import unittest
diff --git a/tests/test_podman_compose_tests.py b/tests/test_podman_compose_tests.py
index 2a09a75..575c90a 100644
--- a/tests/test_podman_compose_tests.py
+++ b/tests/test_podman_compose_tests.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 """
 test_podman_compose_up_down.py
 
diff --git a/tests/test_podman_compose_up_down.py b/tests/test_podman_compose_up_down.py
index 4609196..4e7bba7 100644
--- a/tests/test_podman_compose_up_down.py
+++ b/tests/test_podman_compose_up_down.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
 """
 test_podman_compose_up_down.py