diff --git a/src/nspawn/nspawn-def.h b/src/nspawn/nspawn-def.h
index 9b54cda2f7..ac3a1a02c4 100644
--- a/src/nspawn/nspawn-def.h
+++ b/src/nspawn/nspawn-def.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 #pragma once
 
 #include <sys/types.h>