diff --git a/src/Mod/Plot/CMakeLists.txt b/src/Mod/Plot/CMakeLists.txt
index b3c584b5c7..d280669573 100644
--- a/src/Mod/Plot/CMakeLists.txt
+++ b/src/Mod/Plot/CMakeLists.txt
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 SET(PlotMain_SRCS
     Plot.py
 )
diff --git a/src/Mod/Plot/Plot.py b/src/Mod/Plot/Plot.py
index a3423ae93d..5151c44ed0 100644
--- a/src/Mod/Plot/Plot.py
+++ b/src/Mod/Plot/Plot.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 # ***************************************************************************
 # *   Copyright (c) 2011, 2012 Jose Luis Cercos Pita <jlcercos@gmail.com>   *
 # *                                                                         *