diff --git a/include/osmocom/core/isdnhdlc.h b/include/osmocom/core/isdnhdlc.h
index 43e6e7a..c8cfdc3 100644
--- a/include/osmocom/core/isdnhdlc.h
+++ b/include/osmocom/core/isdnhdlc.h
@@ -22,8 +22,7 @@
  * GNU General Public License for more details.
  */
 
-#ifndef __ISDNHDLC_H__
-#define __ISDNHDLC_H__
+#pragma once
 
 #include <stdint.h>
 
@@ -76,5 +75,3 @@
 
 extern int	osmo_isdnhdlc_encode(struct osmo_isdnhdlc_vars *hdlc, const uint8_t *src,
 				     uint16_t slen, int *count, uint8_t *dst, int dsize);
-
-#endif /* __ISDNHDLC_H__ */
diff --git a/include/osmocom/core/sercomm.h b/include/osmocom/core/sercomm.h
index 072f4d9..38e6271 100644
--- a/include/osmocom/core/sercomm.h
+++ b/include/osmocom/core/sercomm.h
@@ -2,8 +2,7 @@
  *  Osmocom Sercomm HDLC (de)multiplex.
  */
 
-#ifndef _SERCOMM_H
-#define _SERCOMM_H
+#pragma once
 
 #include <osmocom/core/msgb.h>
 
@@ -110,5 +109,3 @@
 }
 
 /*! @} */
-
-#endif /* _SERCOMM_H */
diff --git a/include/osmocom/gsm/protocol/gsm_04_08_gprs.h b/include/osmocom/gsm/protocol/gsm_04_08_gprs.h
index 4729e14..2bc6164 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08_gprs.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08_gprs.h
@@ -1,7 +1,6 @@
 /*! \file gsm_04_08_gprs.h */
 
-#ifndef _GSM48_GPRS_H
-#define _GSM48_GPRS_H
+#pragma once
 
 #include <stdint.h>
 #include <stdbool.h>
@@ -465,6 +464,3 @@
 	/* octet 16 */
 	uint8_t guar_bitrate_down_ext;
 };
-
-
-#endif /* _GSM48_GPRS_H */
diff --git a/include/osmocom/gsm/protocol/gsm_09_02.h b/include/osmocom/gsm/protocol/gsm_09_02.h
index 0b54fb7..4d5ff13 100644
--- a/include/osmocom/gsm/protocol/gsm_09_02.h
+++ b/include/osmocom/gsm/protocol/gsm_09_02.h
@@ -1,8 +1,7 @@
 /*! \file gsm_09_02.h
  * GSM TS 09.02  definitions (MAP). */
 
-#ifndef PROTO_GSM_09_02_H
-#define PROTO_GSM_09_02_H
+#pragma once
 
 /* Section 17.7.4 */
 /* SS-Status */
@@ -134,5 +133,3 @@
 #define GSM0902_TS_CODE_PLMN_SPECIFIC_TS_C			0xDC
 #define GSM0902_TS_CODE_PLMN_SPECIFIC_TS_D			0xDD
 #define GSM0902_TS_CODE_PLMN_SPECIFIC_TS_E			0xDE
-
-#endif /* PROTO_GSM_09_02_H */
diff --git a/include/osmocom/sim/sim.h b/include/osmocom/sim/sim.h
index 5e7099f..639682a 100644
--- a/include/osmocom/sim/sim.h
+++ b/include/osmocom/sim/sim.h
@@ -2,8 +2,7 @@
  * Routines for helping with SIM (ISO/IEC 7816-4 more generally) communication.
  */
 
-#ifndef _OSMOCOM_SIM_H
-#define _OSMOCOM_SIM_H
+#pragma once
 
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/linuxlist.h>
@@ -445,4 +444,3 @@
 struct osim_card_hdl *osim_card_open(struct osim_reader_hdl *rh, enum osim_proto proto);
 int osim_card_reset(struct osim_card_hdl *card, bool cold_reset);
 int osim_card_close(struct osim_card_hdl *card);
-#endif /* _OSMOCOM_SIM_H */