diff --git a/ChangeLog b/ChangeLog
index 478ac3a..a3f9da7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 # ChangeLog for squashmount
 
+*squashmount-22.0.1:
+	Martin Väth <martin at mvath.de>:
+	- Add SPDX-License-Identifier
+
 *squashmount-22.0:
 	Martin Väth <martin at mvath.de>:
 	- Introduce functions to handle rust libraries conveniently:
diff --git a/README.md b/README.md
index 812d433..609966e 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,7 @@
 (C) Martin Väth (martin at mvath.de)
 
 This project is under the BSD license 2.0 (“3-clause BSD license”).
+SPDX-License-Identifier: BSD-3-Clause
 
 Init and management script for mounting rewritable squashfs-compressed data
 
diff --git a/bin/squashmount b/bin/squashmount
index 030e756..9b82d0b 100755
--- a/bin/squashmount
+++ b/bin/squashmount
@@ -1,4 +1,5 @@
 #!/usr/bin/env perl
+# SPDX-License-Identifier: BSD-3-Clause
 BEGIN { require 5.022 }
 package Squashmount v22.0.0;
 
diff --git a/etc/portage/repo.postsync.d/10-squashmount-gentoo b/etc/portage/repo.postsync.d/10-squashmount-gentoo
index 40601a7..ad98bd5 100755
--- a/etc/portage/repo.postsync.d/10-squashmount-gentoo
+++ b/etc/portage/repo.postsync.d/10-squashmount-gentoo
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: BSD-3-Clause
 # This file remounts the squashmount mount-point "gentoo" after each syncing
 # of the "gentoo" repository.
 # Do not use this file if you want to use a mount-point named "gentoo" with
diff --git a/etc/revdep-rebuild/66-squashmount b/etc/revdep-rebuild/66-squashmount
index 45eebf4..bd68b4e 100644
--- a/etc/revdep-rebuild/66-squashmount
+++ b/etc/revdep-rebuild/66-squashmount
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: BSD-3-Clause
 # The python variant of revdep-rebuild requires full paths and " "
 # On the other hand, it accecpts several SEARCH_DIR_MASK entries in one file
 SEARCH_DIRS_MASK="/*/*.mount/readonly"
diff --git a/etc/systemd/system/squashmount.service.d/timeout.conf b/etc/systemd/system/squashmount.service.d/timeout.conf
index 85c6747..c90ccea 100644
--- a/etc/systemd/system/squashmount.service.d/timeout.conf
+++ b/etc/systemd/system/squashmount.service.d/timeout.conf
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: BSD-3-Clause
 [Service]
 # Replace the value by a generous upper bound for the maximally
 # expected compression time on your system:
diff --git a/lib/find_cruft/find_cruft.d/50-squashmount.pl b/lib/find_cruft/find_cruft.d/50-squashmount.pl
index b5c7866..b6a56c8 100644
--- a/lib/find_cruft/find_cruft.d/50-squashmount.pl
+++ b/lib/find_cruft/find_cruft.d/50-squashmount.pl
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: BSD-3-Clause
 # find_cruft should ignore *.mount/{changes,readonly,workdir}
 push(@cutre, '[^/]\.mount/(?:changes|readonly|workdir)$');
 1;
diff --git a/lib/squashmount.pl b/lib/squashmount.pl
index 63c7ed4..9981d19 100644
--- a/lib/squashmount.pl
+++ b/lib/squashmount.pl
@@ -1,4 +1,5 @@
 #!/usr/bin/perl (this is only for editors)
+# SPDX-License-Identifier: BSD-3-Clause
 
 # To use this file as e.g. /etc/squashmount.pl, copy it to that path and
 # remove this comment and the following "fatal()" command from the file
diff --git a/openrc/init.d/squashmount b/openrc/init.d/squashmount
index f4998ea..a27cf8f 100755
--- a/openrc/init.d/squashmount
+++ b/openrc/init.d/squashmount
@@ -1,5 +1,6 @@
 #!/sbin/openrc-run
-# (C) Martin V\"ath <martin@mvath.de>
+# (C) Martin V\"ath <martin at mvath.de>
+# SPDX-License-Identifier: BSD-3-Clause
 
 depend() {
 	need localmount tmpfiles.setup
diff --git a/systemd/system/squashmount.service b/systemd/system/squashmount.service
index c1e1d2f..ad14ae2 100644
--- a/systemd/system/squashmount.service
+++ b/systemd/system/squashmount.service
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: BSD-3-Clause
 [Unit]
 Description=mount/umount all squashmount configured mount points
 After=local-fs.target systemd-tmpfiles-setup.service
diff --git a/tmpfiles.d/squashmount.conf b/tmpfiles.d/squashmount.conf
index 8aebcdc..3833a53 100644
--- a/tmpfiles.d/squashmount.conf
+++ b/tmpfiles.d/squashmount.conf
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: BSD-3-Clause
 # Use "d" or "D" depending on whether /run is on a ramdisk or not.
 # With "D" make sure to run tmpfiles.d only once and before starting squasmount
 d /run/squashmount 0755 root root -
diff --git a/zsh/_squashmount b/zsh/_squashmount
index 3bc858a..133ad52 100644
--- a/zsh/_squashmount
+++ b/zsh/_squashmount
@@ -1,4 +1,5 @@
 #compdef squashmount
+# SPDX-License-Identifier: BSD-3-Clause
 local curcontext="$curcontext" state state_descr line
 typeset -A opt_args
 _arguments -C -s -S : \