diff --git a/ap.c b/ap.c
index db9efb7..4b9157a 100644
--- a/ap.c
+++ b/ap.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <netlink/genl/genl.h>
 #include <netlink/genl/family.h>
diff --git a/bitrate.c b/bitrate.c
index 4a026a4..c0ff319 100644
--- a/bitrate.c
+++ b/bitrate.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 
 #include "nl80211.h"
diff --git a/bloom.c b/bloom.c
index 877a6b5..f697b94 100644
--- a/bloom.c
+++ b/bloom.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <inttypes.h>
 #include "iw.h"
 
diff --git a/coalesce.c b/coalesce.c
index 36dcaef..f3826ca 100644
--- a/coalesce.c
+++ b/coalesce.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 #include <stdio.h>
diff --git a/connect.c b/connect.c
index 3237a27..a486d21 100644
--- a/connect.c
+++ b/connect.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 
 #include <netlink/genl/genl.h>
diff --git a/cqm.c b/cqm.c
index 093b744..4e2e846 100644
--- a/cqm.c
+++ b/cqm.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 
 #include <netlink/genl/genl.h>
diff --git a/event.c b/event.c
index 100f644..a8b4611 100644
--- a/event.c
+++ b/event.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <net/if.h>
diff --git a/ftm.c b/ftm.c
index 23be38e..03eaf38 100644
--- a/ftm.c
+++ b/ftm.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 
 #include <netlink/genl/genl.h>
diff --git a/genl.c b/genl.c
index 7dc27f7..f8dbac3 100644
--- a/genl.c
+++ b/genl.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 /*
  * This ought to be provided by libnl
  */
diff --git a/hwsim.c b/hwsim.c
index 6f82207..fbfaed3 100644
--- a/hwsim.c
+++ b/hwsim.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 
diff --git a/ibss.c b/ibss.c
index f6cbc4c..645639e 100644
--- a/ibss.c
+++ b/ibss.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 #include <strings.h>
diff --git a/ieee80211.h b/ieee80211.h
index 8745608..0a7e205 100644
--- a/ieee80211.h
+++ b/ieee80211.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #ifndef __IEEE80211
 #define __IEEE80211
 
diff --git a/info.c b/info.c
index e6270c8..fc0361d 100644
--- a/info.c
+++ b/info.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <stdbool.h>
 
 #include <netlink/genl/genl.h>
diff --git a/interface.c b/interface.c
index b697482..de5546b 100644
--- a/interface.c
+++ b/interface.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 #include <stdbool.h>
diff --git a/iw.c b/iw.c
index da71617..5bb22c4 100644
--- a/iw.c
+++ b/iw.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 /*
  * nl80211 userspace tool
  *
diff --git a/iw.h b/iw.h
index bc0b3ac..ea7bd6c 100644
--- a/iw.h
+++ b/iw.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #ifndef __IW_H
 #define __IW_H
 
diff --git a/link.c b/link.c
index 1ed7f63..4e73279 100644
--- a/link.c
+++ b/link.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 #include <errno.h>
 #include <string.h>
diff --git a/measurements.c b/measurements.c
index 385143f..54ca402 100644
--- a/measurements.c
+++ b/measurements.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 
 #include "nl80211.h"
diff --git a/mesh.c b/mesh.c
index 0650d0c..2591a4b 100644
--- a/mesh.c
+++ b/mesh.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 
diff --git a/mgmt.c b/mgmt.c
index 338435d..8639f9c 100644
--- a/mgmt.c
+++ b/mgmt.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <string.h>
 #include <errno.h>
 
diff --git a/mpath.c b/mpath.c
index e39c24b..3cb465b 100644
--- a/mpath.c
+++ b/mpath.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 #include <errno.h>
 #include <string.h>
diff --git a/mpp.c b/mpp.c
index 58bf28e..23193a4 100644
--- a/mpp.c
+++ b/mpp.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 #include <errno.h>
 
diff --git a/nan.c b/nan.c
index 1d8d795..a846b68 100644
--- a/nan.c
+++ b/nan.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 #include <errno.h>
 #include <string.h>
diff --git a/nl80211.h b/nl80211.h
index 6f09d15..750b116 100644
--- a/nl80211.h
+++ b/nl80211.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #ifndef __LINUX_NL80211_H
 #define __LINUX_NL80211_H
 /*
diff --git a/ocb.c b/ocb.c
index fc9579b..1678e49 100644
--- a/ocb.c
+++ b/ocb.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 
diff --git a/offch.c b/offch.c
index 19e170e..684eea3 100644
--- a/offch.c
+++ b/offch.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 
 #include <netlink/genl/genl.h>
diff --git a/p2p.c b/p2p.c
index 2d4bab0..1d12046 100644
--- a/p2p.c
+++ b/p2p.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <netlink/genl/genl.h>
 #include <netlink/genl/family.h>
 #include <netlink/genl/ctrl.h>
diff --git a/phy.c b/phy.c
index 716677e..a5159c7 100644
--- a/phy.c
+++ b/phy.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <stdbool.h>
 #include <errno.h>
 #include <strings.h>
diff --git a/ps.c b/ps.c
index de36d2b..67f7a38 100644
--- a/ps.c
+++ b/ps.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 
diff --git a/reason.c b/reason.c
index f91c681..74f516b 100644
--- a/reason.c
+++ b/reason.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <stdint.h>
 #include "iw.h"
 
diff --git a/reg.c b/reg.c
index a2368df..7a83df2 100644
--- a/reg.c
+++ b/reg.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 #include <stdbool.h>
diff --git a/roc.c b/roc.c
index c6eda10..a159487 100644
--- a/roc.c
+++ b/roc.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 
diff --git a/scan.c b/scan.c
index 6ad3ad4..1993f0b 100644
--- a/scan.c
+++ b/scan.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 #include <errno.h>
 #include <string.h>
diff --git a/sections.c b/sections.c
index 38095f6..3b0ec8b 100644
--- a/sections.c
+++ b/sections.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include "iw.h"
 
 SECTION(get);
diff --git a/sha256.c b/sha256.c
index 4a43df8..da9d967 100644
--- a/sha256.c
+++ b/sha256.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include "sha256.h"
 
 /**
diff --git a/sha256.h b/sha256.h
index d3eb3c0..4a32604 100644
--- a/sha256.h
+++ b/sha256.h
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #ifndef SHA256
 #define SHA256
 
diff --git a/station.c b/station.c
index aaad079..d8f0ae3 100644
--- a/station.c
+++ b/station.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 #include <errno.h>
 #include <string.h>
diff --git a/status.c b/status.c
index 731727d..7529021 100644
--- a/status.c
+++ b/status.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <stdint.h>
 #include "iw.h"
 
diff --git a/survey.c b/survey.c
index 9325353..ffaf85a 100644
--- a/survey.c
+++ b/survey.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <net/if.h>
 
 #include <netlink/genl/genl.h>
diff --git a/util.c b/util.c
index 41277b5..55993c7 100644
--- a/util.c
+++ b/util.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <ctype.h>
 #include <netlink/attr.h>
 #include <errno.h>
diff --git a/vendor.c b/vendor.c
index d203d85..7610354 100644
--- a/vendor.c
+++ b/vendor.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 
diff --git a/wowlan.c b/wowlan.c
index 778c0db..71392d1 100644
--- a/wowlan.c
+++ b/wowlan.c
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: ISC */
+
 #include <errno.h>
 #include <string.h>
 #include <stdio.h>
