diff --git a/include/libpldm/base.h b/include/libpldm/base.h
index 8ec821f..97c3578 100644
--- a/include/libpldm/base.h
+++ b/include/libpldm/base.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef BASE_H
 #define BASE_H
 
diff --git a/include/libpldm/bios.h b/include/libpldm/bios.h
index 8b0f7d9..25636bf 100644
--- a/include/libpldm/bios.h
+++ b/include/libpldm/bios.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef BIOS_H
 #define BIOS_H
 
diff --git a/include/libpldm/bios_table.h b/include/libpldm/bios_table.h
index 0239f3d..32f7451 100644
--- a/include/libpldm/bios_table.h
+++ b/include/libpldm/bios_table.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef LIBPLDM_BIOS_TABLE_H
 #define LIBPLDM_BIOS_TABLE_H
 
diff --git a/include/libpldm/entity.h b/include/libpldm/entity.h
index 9e657c1..ab2c175 100644
--- a/include/libpldm/entity.h
+++ b/include/libpldm/entity.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef ENTITY_H
 #define ENTITY_H
 
diff --git a/include/libpldm/firmware_update.h b/include/libpldm/firmware_update.h
index fe89b41..46cfcca 100644
--- a/include/libpldm/firmware_update.h
+++ b/include/libpldm/firmware_update.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef FW_UPDATE_H
 #define FW_UPDATE_H
 
diff --git a/include/libpldm/fru.h b/include/libpldm/fru.h
index a369b9d..3a066aa 100644
--- a/include/libpldm/fru.h
+++ b/include/libpldm/fru.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef FRU_H
 #define FRU_H
 
diff --git a/include/libpldm/instance-id.h b/include/libpldm/instance-id.h
index eebaecb..36094b9 100644
--- a/include/libpldm/instance-id.h
+++ b/include/libpldm/instance-id.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef INSTANCE_ID_H
 #define INSTANCE_ID_H
 
diff --git a/include/libpldm/oem/ibm/libpldm/entity_oem_ibm.h b/include/libpldm/oem/ibm/libpldm/entity_oem_ibm.h
index dd80f56..5b84ff9 100644
--- a/include/libpldm/oem/ibm/libpldm/entity_oem_ibm.h
+++ b/include/libpldm/oem/ibm/libpldm/entity_oem_ibm.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef OEM_IBM_ENTITY_H
 #define OEM_IBM_ENTITY_H
 
diff --git a/include/libpldm/oem/ibm/libpldm/file_io.h b/include/libpldm/oem/ibm/libpldm/file_io.h
index c512363..28c2552 100644
--- a/include/libpldm/oem/ibm/libpldm/file_io.h
+++ b/include/libpldm/oem/ibm/libpldm/file_io.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef FILEIO_H
 #define FILEIO_H
 
diff --git a/include/libpldm/oem/ibm/libpldm/fru_oem_ibm.h b/include/libpldm/oem/ibm/libpldm/fru_oem_ibm.h
index c97f8b0..18275f1 100644
--- a/include/libpldm/oem/ibm/libpldm/fru_oem_ibm.h
+++ b/include/libpldm/oem/ibm/libpldm/fru_oem_ibm.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef OEM_IBM_FRU_H
 #define OEM_IBM_FRU_H
 
diff --git a/include/libpldm/oem/ibm/libpldm/host.h b/include/libpldm/oem/ibm/libpldm/host.h
index ed121ae..3dff220 100644
--- a/include/libpldm/oem/ibm/libpldm/host.h
+++ b/include/libpldm/oem/ibm/libpldm/host.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef OEM_IBM_HOST_H
 #define OEM_IBM_HOST_H
 
diff --git a/include/libpldm/oem/ibm/libpldm/platform_oem_ibm.h b/include/libpldm/oem/ibm/libpldm/platform_oem_ibm.h
index b0c781c..34b3f4e 100644
--- a/include/libpldm/oem/ibm/libpldm/platform_oem_ibm.h
+++ b/include/libpldm/oem/ibm/libpldm/platform_oem_ibm.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef PLATFORM_OEM_IBM_H
 #define PLATFORM_OEM_IBM_H
 
diff --git a/include/libpldm/oem/ibm/libpldm/state_set_oem_ibm.h b/include/libpldm/oem/ibm/libpldm/state_set_oem_ibm.h
index 5c8378b..9f8fee8 100644
--- a/include/libpldm/oem/ibm/libpldm/state_set_oem_ibm.h
+++ b/include/libpldm/oem/ibm/libpldm/state_set_oem_ibm.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef STATE_SET_OEM_IBM_H
 #define STATE_SET_OEM_IBM_H
 
diff --git a/include/libpldm/pdr.h b/include/libpldm/pdr.h
index 4293d75..b62b23b 100644
--- a/include/libpldm/pdr.h
+++ b/include/libpldm/pdr.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef PDR_H
 #define PDR_H
 
diff --git a/include/libpldm/platform.h b/include/libpldm/platform.h
index 03243b4..251188b 100644
--- a/include/libpldm/platform.h
+++ b/include/libpldm/platform.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef PLATFORM_H
 #define PLATFORM_H
 
diff --git a/include/libpldm/pldm_types.h b/include/libpldm/pldm_types.h
index e48cb8c..e6c8985 100644
--- a/include/libpldm/pldm_types.h
+++ b/include/libpldm/pldm_types.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef PLDM_TYPES_H
 #define PLDM_TYPES_H
 
diff --git a/include/libpldm/requester/pldm.h b/include/libpldm/requester/pldm.h
index 6b84acb..d36c4c9 100644
--- a/include/libpldm/requester/pldm.h
+++ b/include/libpldm/requester/pldm.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef MCTP_H
 #define MCTP_H
 
diff --git a/include/libpldm/state_set.h b/include/libpldm/state_set.h
index e47c476..c3097cb 100644
--- a/include/libpldm/state_set.h
+++ b/include/libpldm/state_set.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef STATE_SET_H
 #define STATE_SET_H
 
diff --git a/include/libpldm/states.h b/include/libpldm/states.h
index a89648d..d1a8e37 100644
--- a/include/libpldm/states.h
+++ b/include/libpldm/states.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef STATES_H
 #define STATES_H
 
diff --git a/include/libpldm/transport.h b/include/libpldm/transport.h
index 660ff02..97c51d4 100644
--- a/include/libpldm/transport.h
+++ b/include/libpldm/transport.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef TRANSPORT_PLDM_H
 #define TRANSPORT_PLDM_H
 
diff --git a/include/libpldm/utils.h b/include/libpldm/utils.h
index 93720a4..8deec34 100644
--- a/include/libpldm/utils.h
+++ b/include/libpldm/utils.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef LIBPLDM_UTILS_H
 #define LIBPLDM_UTILS_H
 
diff --git a/src/array.h b/src/array.h
index 05f26bd..45e83aa 100644
--- a/src/array.h
+++ b/src/array.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef LIBPLDM_SRC_ARRAY_H
 #define LIBPLDM_SRC_ARRAY_H
 
diff --git a/src/base.c b/src/base.c
index 908621b..4322ef2 100644
--- a/src/base.c
+++ b/src/base.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "base.h"
 #include "pldm_types.h"
 #include <endian.h>
diff --git a/src/bios.c b/src/bios.c
index 45dc897..83c6dc9 100644
--- a/src/bios.c
+++ b/src/bios.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "bios.h"
 #include "base.h"
 #include "utils.h"
diff --git a/src/bios_table.c b/src/bios_table.c
index db1a6be..228bff4 100644
--- a/src/bios_table.c
+++ b/src/bios_table.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "array.h"
 #include "bios_table.h"
 #include "base.h"
diff --git a/src/firmware_update.c b/src/firmware_update.c
index 3cab7d0..22b4387 100644
--- a/src/firmware_update.c
+++ b/src/firmware_update.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "firmware_update.h"
 #include "utils.h"
 #include <endian.h>
diff --git a/src/fru.c b/src/fru.c
index b0cb864..024a34f 100644
--- a/src/fru.c
+++ b/src/fru.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include <assert.h>
 #include <endian.h>
 #include <stdbool.h>
diff --git a/src/mctp-defines.h b/src/mctp-defines.h
index 912d47c..620115f 100644
--- a/src/mctp-defines.h
+++ b/src/mctp-defines.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef MCTP_DEFINES_H
 #define MCTP_DEFINES_H
 
diff --git a/src/msgbuf.h b/src/msgbuf.h
index 128b4be..4c0e61c 100644
--- a/src/msgbuf.h
+++ b/src/msgbuf.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef PLDM_MSGBUF_H
 #define PLDM_MSGBUF_H
 
diff --git a/src/msgbuf/platform.h b/src/msgbuf/platform.h
index bc296b8..3fbe077 100644
--- a/src/msgbuf/platform.h
+++ b/src/msgbuf/platform.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef PLDM_MSGBUF_PLATFORM_H
 #define PLDM_MSGBUF_PLATFORM_H
 
diff --git a/src/oem/ibm/file_io.c b/src/oem/ibm/file_io.c
index 05b81c6..ba0111a 100644
--- a/src/oem/ibm/file_io.c
+++ b/src/oem/ibm/file_io.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "libpldm/file_io.h"
 #include "base.h"
 #include <endian.h>
diff --git a/src/oem/ibm/host.c b/src/oem/ibm/host.c
index 04ba5f3..c94ee49 100644
--- a/src/oem/ibm/host.c
+++ b/src/oem/ibm/host.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "base.h"
 #include <endian.h>
 #include <stdint.h>
diff --git a/src/oem/ibm/platform.c b/src/oem/ibm/platform.c
index 462f378..3a8b2f8 100644
--- a/src/oem/ibm/platform.c
+++ b/src/oem/ibm/platform.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "libpldm/platform.h"
 #include "libpldm/platform_oem_ibm.h"
 #include <string.h>
diff --git a/src/pdr.c b/src/pdr.c
index 72cab7e..ee699c7 100644
--- a/src/pdr.c
+++ b/src/pdr.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "pdr.h"
 #include "platform.h"
 #include <assert.h>
diff --git a/src/platform.c b/src/platform.c
index 8619772..a24cd30 100644
--- a/src/platform.c
+++ b/src/platform.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "msgbuf/platform.h"
 #include "base.h"
 #include "msgbuf.h"
diff --git a/src/requester/instance-id.c b/src/requester/instance-id.c
index a079f7b..108e451 100644
--- a/src/requester/instance-id.c
+++ b/src/requester/instance-id.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 // NOLINTNEXTLINE(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp)
 #define _GNU_SOURCE
 #include "libpldm/instance-id.h"
diff --git a/src/requester/pldm.c b/src/requester/pldm.c
index 30687b3..9e6801a 100644
--- a/src/requester/pldm.c
+++ b/src/requester/pldm.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "libpldm/requester/pldm.h"
 #include "base.h"
 #include "libpldm/transport.h"
diff --git a/src/responder.c b/src/responder.c
index 5112f7b..9940fa0 100644
--- a/src/responder.c
+++ b/src/responder.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "responder.h"
 
 #include <libpldm/base.h>
diff --git a/src/responder.h b/src/responder.h
index 37df828..1295cda 100644
--- a/src/responder.h
+++ b/src/responder.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef LIBPLDM_SRC_RESPONDER_H
 #define LIBPLDM_SRC_RESPONDER_H
 
diff --git a/src/transport/af-mctp.c b/src/transport/af-mctp.c
index 34454b3..bf024b8 100644
--- a/src/transport/af-mctp.c
+++ b/src/transport/af-mctp.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "mctp-defines.h"
 #include "base.h"
 #include "container-of.h"
diff --git a/src/transport/container-of.h b/src/transport/container-of.h
index facefe5..4c6ce1b 100644
--- a/src/transport/container-of.h
+++ b/src/transport/container-of.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef CONTAINER_OF_H
 #define CONTAINER_OF_H
 
diff --git a/src/transport/mctp-demux.c b/src/transport/mctp-demux.c
index 8b35c0a..a874cef 100644
--- a/src/transport/mctp-demux.c
+++ b/src/transport/mctp-demux.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "mctp-defines.h"
 #include "base.h"
 #include "container-of.h"
diff --git a/src/transport/socket.c b/src/transport/socket.c
index 8c5dd01..4498356 100644
--- a/src/transport/socket.c
+++ b/src/transport/socket.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "socket.h"
 
 #include <errno.h>
diff --git a/src/transport/socket.h b/src/transport/socket.h
index 17751ca..09c697a 100644
--- a/src/transport/socket.h
+++ b/src/transport/socket.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef LIBPLDM_SRC_TRANSPORT_SOCKET_H
 #define LIBPLDM_SRC_TRANSPORT_SOCKET_H
 
diff --git a/src/transport/test.c b/src/transport/test.c
index 730d8e6..2a929cc 100644
--- a/src/transport/test.c
+++ b/src/transport/test.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 /* NOLINTNEXTLINE(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp) */
 #define _GNU_SOURCE
 #include "array.h"
diff --git a/src/transport/transport.c b/src/transport/transport.c
index 12a26aa..bc01000 100644
--- a/src/transport/transport.c
+++ b/src/transport/transport.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "libpldm/transport.h"
 #include "libpldm/base.h"
 #include "libpldm/requester/pldm.h"
diff --git a/src/transport/transport.h b/src/transport/transport.h
index f052785..81d7b61 100644
--- a/src/transport/transport.h
+++ b/src/transport/transport.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #ifndef LIBPLDM_SRC_TRANSPORT_TRANSPORT_H
 #define LIBPLDM_SRC_TRANSPORT_TRANSPORT_H
 
diff --git a/src/utils.c b/src/utils.c
index f6a2b7b..0e24da5 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 #include "utils.h"
 #include "base.h"
 #include <limits.h>
diff --git a/tests/bios_table_iter.c b/tests/bios_table_iter.c
index f8da402..1e9840a 100644
--- a/tests/bios_table_iter.c
+++ b/tests/bios_table_iter.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 /* Force elision of assert() */
 #ifndef NDEBUG
 #define NDEBUG
diff --git a/tests/msgbuf_generic.c b/tests/msgbuf_generic.c
index d79d442..3307917 100644
--- a/tests/msgbuf_generic.c
+++ b/tests/msgbuf_generic.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
 /* Test pldm_msgbuf_extract() separately because we can't do _Generic() in C++
  * code, i.e. gtest */