diff --git a/core/include/cond.h b/core/include/cond.h
index 4db672d940..ee1237d9fa 100644
--- a/core/include/cond.h
+++ b/core/include/cond.h
@@ -4,6 +4,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_sync_cond Condition Variable
  * @ingroup     core_sync
@@ -134,9 +136,6 @@
  * @author      Sam Kumar <samkumar@berkeley.edu>
  */
 
-#ifndef COND_H
-#define COND_H
-
 #include <stdbool.h>
 #include <stddef.h>
 
@@ -211,5 +210,4 @@ void cond_broadcast(cond_t *cond);
 }
 #endif
 
-#endif /* COND_H */
 /** @} */
diff --git a/core/include/mbox.h b/core/include/mbox.h
index 121b9ae65a..aa12657998 100644
--- a/core/include/mbox.h
+++ b/core/include/mbox.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_mbox Mailboxes
  * @ingroup     core
@@ -19,9 +21,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef MBOX_H
-#define MBOX_H
-
 #include "list.h"
 #include "cib.h"
 #include "msg.h"
@@ -201,4 +200,3 @@ static inline void mbox_unset(mbox_t *mbox)
 #endif
 
 /** @} */
-#endif /* MBOX_H */
diff --git a/core/include/msg.h b/core/include/msg.h
index f934c49f07..758a6ca6a6 100644
--- a/core/include/msg.h
+++ b/core/include/msg.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_msg  Messaging / IPC
  * @ingroup     core
@@ -173,9 +175,6 @@
  * @author      Kévin Roussel <Kevin.Roussel@inria.fr>
  */
 
-#ifndef MSG_H
-#define MSG_H
-
 #include <stdint.h>
 #include <stdbool.h>
 
@@ -434,5 +433,4 @@ void msg_queue_print(void);
 }
 #endif
 
-#endif /* MSG_H */
 /** @} */
diff --git a/core/include/msg_bus.h b/core/include/msg_bus.h
index ef1c29c13c..f2ed3b3a0a 100644
--- a/core/include/msg_bus.h
+++ b/core/include/msg_bus.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_msg
  *
@@ -35,9 +37,6 @@
  * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
  */
 
-#ifndef MSG_BUS_H
-#define MSG_BUS_H
-
 #include <assert.h>
 #include <stdint.h>
 
@@ -264,5 +263,4 @@ static inline int msg_bus_post(msg_bus_t *bus, uint8_t type, const void *arg)
 }
 #endif
 
-#endif /* MSG_BUS_H */
 /** @} */
diff --git a/core/include/mutex.h b/core/include/mutex.h
index 79781a330c..6f94e9dbc9 100644
--- a/core/include/mutex.h
+++ b/core/include/mutex.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @addtogroup     core_sync_mutex
  * @{
@@ -18,9 +20,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef MUTEX_H
-#define MUTEX_H
-
 #include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
@@ -349,5 +348,4 @@ void mutex_cancel(mutex_cancel_t *mc);
 }
 #endif
 
-#endif /* MUTEX_H */
 /** @} */
diff --git a/core/include/native_sched.h b/core/include/native_sched.h
index 18c22191f5..6757d66e59 100644
--- a/core/include/native_sched.h
+++ b/core/include/native_sched.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_sched_native Scheduler for native
  * @ingroup     core_sched
@@ -20,9 +22,6 @@
  * @author      Raphael Hiesgen <raphael.hiesgen@haw-hamburg.de>
  */
 
-#ifndef NATIVE_SCHED_H
-#define NATIVE_SCHED_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -64,5 +63,4 @@ extern int sched_yield(void);
 }
 #endif
 
-#endif /* NATIVE_SCHED_H */
 /** @} */
diff --git a/core/include/sched.h b/core/include/sched.h
index f7384236ff..1b4c6bad7e 100644
--- a/core/include/sched.h
+++ b/core/include/sched.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_sched Scheduler
  * @ingroup     core
@@ -78,9 +80,6 @@
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
-#ifndef SCHED_H
-#define SCHED_H
-
 #include <stddef.h>
 #include <inttypes.h>
 
@@ -385,5 +384,4 @@ static inline int sched_runq_more_than_one(uint8_t prio)
 }
 #endif
 
-#endif /* SCHED_H */
 /** @} */
diff --git a/core/include/stdio.h b/core/include/stdio.h
index cb70c636df..3c335610d7 100644
--- a/core/include/stdio.h
+++ b/core/include/stdio.h
@@ -6,6 +6,8 @@
  * details.
  */
 
+#pragma once
+
 /**
  * @ingroup     sys_stdio_null
  *
@@ -22,8 +24,6 @@
  * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
  */
 
-#ifndef CORE_STDIO_H
-#define CORE_STDIO_H
 #include_next "stdio.h"
 
 #ifdef MODULE_STDIO_NULL
@@ -66,5 +66,4 @@ static inline int vprintf_null(const char *__restrict__ format, va_list ap)
 
 #endif  /* MODULE_STDIO_NULL */
 
-#endif  /* CORE_STDIO_H */
 /** @} */
diff --git a/core/include/thread.h b/core/include/thread.h
index c226306ef1..1c57cb03f8 100644
--- a/core/include/thread.h
+++ b/core/include/thread.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_thread Threading
  * @ingroup     core
@@ -116,9 +118,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef THREAD_H
-#define THREAD_H
-
 #include "clist.h"
 #include "cib.h"
 #include "msg.h"
@@ -660,4 +659,3 @@ static inline uintptr_t thread_measure_stack_free(const thread_t *thread)
 #endif
 
 /** @} */
-#endif /* THREAD_H */
diff --git a/core/include/thread_flags.h b/core/include/thread_flags.h
index 846fcb64e4..93bc0c5504 100644
--- a/core/include/thread_flags.h
+++ b/core/include/thread_flags.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_thread_flags Thread Flags
  * @ingroup     core
@@ -54,9 +56,6 @@
  *
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
-#ifndef THREAD_FLAGS_H
-#define THREAD_FLAGS_H
-
 #include "sched.h"  /* for thread_t typedef */
 
 #ifdef __cplusplus
@@ -201,5 +200,4 @@ int thread_flags_wake(thread_t *thread);
 }
 #endif
 
-#endif /* THREAD_FLAGS_H */
 /** @} */
diff --git a/core/lib/include/assert.h b/core/lib/include/assert.h
index 322926cae1..8891a95cc2 100644
--- a/core/lib/include/assert.h
+++ b/core/lib/include/assert.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  *
@@ -19,9 +21,6 @@
  * @author      Martine Lenders <m.lenders@fu-berlin.de>
  */
 
-#ifndef ASSERT_H
-#define ASSERT_H
-
 #include <stdint.h>
 
 #ifdef __cplusplus
@@ -169,5 +168,4 @@ __NORETURN void _assert_panic(void);
 }
 #endif
 
-#endif /* ASSERT_H */
 /** @} */
diff --git a/core/lib/include/bitarithm.h b/core/lib/include/bitarithm.h
index ac2a88c402..29aa78a4a1 100644
--- a/core/lib/include/bitarithm.h
+++ b/core/lib/include/bitarithm.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -18,9 +20,6 @@
  * @author      Martine Lenders <mlenders@inf.fu-berlin.de>
  */
 
-#ifndef BITARITHM_H
-#define BITARITHM_H
-
 #include <stdint.h>
 
 #include "cpu_conf.h"
@@ -278,5 +277,4 @@ static inline unsigned bitarithm_test_and_clear(unsigned state, uint8_t *index)
 }
 #endif
 
-#endif /* BITARITHM_H */
 /** @} */
diff --git a/core/lib/include/cib.h b/core/lib/include/cib.h
index 5743bb6af8..6d9ce40f82 100644
--- a/core/lib/include/cib.h
+++ b/core/lib/include/cib.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -30,9 +32,6 @@
  *              exclusive access as indicated in the API doc.
  */
 
-#ifndef CIB_H
-#define CIB_H
-
 #include "assert.h"
 
 #ifdef __cplusplus
@@ -285,5 +284,4 @@ static inline int cib_put_unsafe(cib_t *cib)
 }
 #endif
 
-#endif /* CIB_H */
 /** @} */
diff --git a/core/lib/include/clist.h b/core/lib/include/clist.h
index 27853e0fcd..c646921e57 100644
--- a/core/lib/include/clist.h
+++ b/core/lib/include/clist.h
@@ -8,6 +8,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -87,9 +89,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef CLIST_H
-#define CLIST_H
-
 #include <stdbool.h>
 #include <stddef.h>
 #include "list.h"
@@ -500,5 +499,4 @@ static inline bool clist_more_than_one(clist_node_t *list)
 }
 #endif
 
-#endif /* CLIST_H */
 /** @} */
diff --git a/core/lib/include/compiler_hints.h b/core/lib/include/compiler_hints.h
index 7d3bc8583f..f056671119 100644
--- a/core/lib/include/compiler_hints.h
+++ b/core/lib/include/compiler_hints.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_internal
  * @{
@@ -18,9 +20,6 @@
  * @author      Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
  */
 
-#ifndef COMPILER_HINTS_H
-#define COMPILER_HINTS_H
-
 #include <assert.h>
 #include <stdint.h>
 
@@ -198,5 +197,4 @@ static inline unsigned may_be_zero(unsigned n)
 }
 #endif
 
-#endif /* COMPILER_HINTS_H */
 /** @} */
diff --git a/core/lib/include/container.h b/core/lib/include/container.h
index 98ffe557ce..1473760d27 100644
--- a/core/lib/include/container.h
+++ b/core/lib/include/container.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_internal
  * @{
@@ -18,9 +20,6 @@
  * @author      Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
  */
 
-#ifndef CONTAINER_H
-#define CONTAINER_H
-
 #include <stddef.h>
 #include <stdint.h>
 
@@ -87,5 +86,4 @@ extern "C" {
 }
 #endif
 
-#endif /* CONTAINER_H */
 /** @} */
diff --git a/core/lib/include/debug.h b/core/lib/include/debug.h
index e1337ba795..620de78267 100644
--- a/core/lib/include/debug.h
+++ b/core/lib/include/debug.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -21,9 +23,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef DEBUG_H
-#define DEBUG_H
-
 #include <stdio.h>
 #include "sched.h"
 #include "thread.h"
@@ -148,5 +147,4 @@ extern "C" {
 }
 #endif
 
-#endif /* DEBUG_H */
 /** @} */
diff --git a/core/lib/include/irq.h b/core/lib/include/irq.h
index 64c6c09787..37990dab3c 100644
--- a/core/lib/include/irq.h
+++ b/core/lib/include/irq.h
@@ -6,6 +6,9 @@
  * directory for more details.
  */
 
+#ifndef IRQ_H
+#define IRQ_H
+
 /**
  * @defgroup    core_irq     IRQ Handling
  * @ingroup     core
@@ -19,9 +22,6 @@
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
-#ifndef IRQ_H
-#define IRQ_H
-
 #include <stdbool.h>
 #include "cpu_conf.h"
 
@@ -30,9 +30,9 @@ extern "C" {
 #endif
 
 #ifdef IRQ_API_INLINED
-#define MAYBE_INLINE static inline __attribute__((always_inline))
+#  define MAYBE_INLINE static inline __attribute__((always_inline))
 #else
-#define MAYBE_INLINE
+#  define MAYBE_INLINE
 #endif /* IRQ_API_INLINED */
 
 #ifndef IRQ_API_INLINED
@@ -91,12 +91,12 @@ MAYBE_INLINE bool irq_is_enabled(void);
 MAYBE_INLINE bool irq_is_in(void);
 
 #else
-#include "irq_arch.h" /* IWYU pragma: export */
-#endif /* IRQ_API_INLINED */
+#  include "irq_arch.h" /* IWYU pragma: export */
+#endif                  /* IRQ_API_INLINED */
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* IRQ_H */
 /** @} */
+#endif /* IRQ_H */
diff --git a/core/lib/include/kernel_defines.h b/core/lib/include/kernel_defines.h
index 9698477fb1..92034baad3 100644
--- a/core/lib/include/kernel_defines.h
+++ b/core/lib/include/kernel_defines.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_internal
  * @{
@@ -18,9 +20,6 @@
  * @author      Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
  */
 
-#ifndef KERNEL_DEFINES_H
-#define KERNEL_DEFINES_H
-
 #include "modules.h"
 #include "riot_version.h"
 #include "compiler_hints.h"
@@ -34,5 +33,4 @@ extern "C" {
 }
 #endif
 
-#endif /* KERNEL_DEFINES_H */
 /** @} */
diff --git a/core/lib/include/kernel_init.h b/core/lib/include/kernel_init.h
index 2e724d5ae0..018141e2e3 100644
--- a/core/lib/include/kernel_init.h
+++ b/core/lib/include/kernel_init.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_internal
  * @{
@@ -18,9 +20,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef KERNEL_INIT_H
-#define KERNEL_INIT_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -69,5 +68,4 @@ static inline void early_init(void) {}
 }
 #endif
 
-#endif /* KERNEL_INIT_H */
 /** @} */
diff --git a/core/lib/include/list.h b/core/lib/include/list.h
index 1eb477118b..2bed483b0c 100644
--- a/core/lib/include/list.h
+++ b/core/lib/include/list.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -20,9 +22,6 @@
  * @author      Víctor Ariño <victor.arino@zii.aero>
  */
 
-#ifndef LIST_H
-#define LIST_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -99,5 +98,4 @@ static inline list_node_t *list_remove(list_node_t *list, list_node_t *node)
 }
 #endif
 
-#endif /* LIST_H */
 /** @} */
diff --git a/core/lib/include/log.h b/core/lib/include/log.h
index 026b3c405b..1fb65f4bae 100644
--- a/core/lib/include/log.h
+++ b/core/lib/include/log.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -30,9 +32,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef LOG_H
-#define LOG_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -124,5 +123,4 @@ enum {
 }
 #endif
 
-#endif /* LOG_H */
 /** @} */
diff --git a/core/lib/include/macros/math.h b/core/lib/include/macros/math.h
index cf7c374445..1eea61c9f9 100644
--- a/core/lib/include/macros/math.h
+++ b/core/lib/include/macros/math.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_macros
  * @{
@@ -16,9 +18,6 @@
  * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
  */
 
-#ifndef MACROS_MATH_H
-#define MACROS_MATH_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -57,5 +56,4 @@ extern "C" {
 }
 #endif
 
-#endif /* MACROS_MATH_H */
 /** @} */
diff --git a/core/lib/include/macros/units.h b/core/lib/include/macros/units.h
index ff3a6ca98d..ec7c4f999e 100644
--- a/core/lib/include/macros/units.h
+++ b/core/lib/include/macros/units.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_macros
  * @{
@@ -16,9 +18,6 @@
  * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
  */
 
-#ifndef MACROS_UNITS_H
-#define MACROS_UNITS_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -57,5 +56,4 @@ extern "C" {
 }
 #endif
 
-#endif /* MACROS_UNITS_H */
 /** @} */
diff --git a/core/lib/include/macros/utils.h b/core/lib/include/macros/utils.h
index d3ec5027ac..30ee3bd425 100644
--- a/core/lib/include/macros/utils.h
+++ b/core/lib/include/macros/utils.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_macros
  * @{
@@ -16,9 +18,6 @@
  * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
  */
 
-#ifndef MACROS_UTILS_H
-#define MACROS_UTILS_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -93,5 +92,4 @@ extern "C" {
 }
 #endif
 
-#endif /* MACROS_UTILS_H */
 /** @} */
diff --git a/core/lib/include/macros/xtstr.h b/core/lib/include/macros/xtstr.h
index 8e36da15c7..850ebecada 100644
--- a/core/lib/include/macros/xtstr.h
+++ b/core/lib/include/macros/xtstr.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_macros
  * @{
@@ -16,9 +18,6 @@
  * @author      Gunar Schorcht <gunar@schorcht.net>
  */
 
-#ifndef MACROS_XTSTR_H
-#define MACROS_XTSTR_H
-
 #include <stddef.h>
 
 #ifdef __cplusplus
@@ -41,5 +40,4 @@ extern "C" {
 }
 #endif
 
-#endif /* MACROS_XTSTR_H */
 /** @} */
diff --git a/core/lib/include/modules.h b/core/lib/include/modules.h
index 8310cf36d6..7a555b65c4 100644
--- a/core/lib/include/modules.h
+++ b/core/lib/include/modules.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_internal
  * @{
@@ -18,9 +20,6 @@
  * @author      Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
  */
 
-#ifndef MODULES_H
-#define MODULES_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -107,5 +106,4 @@ extern "C" {
 }
 #endif
 
-#endif /* MODULES_H */
 /** @} */
diff --git a/core/lib/include/panic.h b/core/lib/include/panic.h
index 7c86861ef0..07b67d5a46 100644
--- a/core/lib/include/panic.h
+++ b/core/lib/include/panic.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -19,9 +21,6 @@
  * @author      Kévin Roussel <Kevin.Roussel@inria.fr>
  */
 
-#ifndef PANIC_H
-#define PANIC_H
-
 #include "kernel_defines.h"
 
 #ifdef __cplusplus
@@ -100,5 +99,4 @@ void panic_arch(void);
 }
 #endif
 
-#endif /* PANIC_H */
 /** @} */
diff --git a/core/lib/include/priority_queue.h b/core/lib/include/priority_queue.h
index b23527fca6..1ca2660848 100644
--- a/core/lib/include/priority_queue.h
+++ b/core/lib/include/priority_queue.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -16,9 +18,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef PRIORITY_QUEUE_H
-#define PRIORITY_QUEUE_H
-
 #include <stddef.h>
 #include <stdint.h>
 
@@ -139,4 +138,3 @@ void priority_queue_print_node(priority_queue_t *root);
 #endif
 
 /** @} */
-#endif /* PRIORITY_QUEUE_H */
diff --git a/core/lib/include/ringbuffer.h b/core/lib/include/ringbuffer.h
index 3601f8291e..88bbee43b3 100644
--- a/core/lib/include/ringbuffer.h
+++ b/core/lib/include/ringbuffer.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @{
@@ -22,9 +24,6 @@
  * @}
  */
 
-#ifndef RINGBUFFER_H
-#define RINGBUFFER_H
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -163,5 +162,3 @@ unsigned ringbuffer_peek(const ringbuffer_t *__restrict rb, char *buf,
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* RINGBUFFER_H */
diff --git a/core/lib/include/riot_version.h b/core/lib/include/riot_version.h
index 688b1c9d27..e69346fb03 100644
--- a/core/lib/include/riot_version.h
+++ b/core/lib/include/riot_version.h
@@ -7,6 +7,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_internal
  * @{
@@ -18,9 +20,6 @@
  * @author      Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
  */
 
-#ifndef RIOT_VERSION_H
-#define RIOT_VERSION_H
-
 #include <stdint.h>
 
 #ifdef __cplusplus
@@ -60,5 +59,4 @@ extern "C" {
 }
 #endif
 
-#endif /* RIOT_VERSION_H */
 /** @} */
diff --git a/core/lib/include/rmutex.h b/core/lib/include/rmutex.h
index 7a3daa7146..c80927d2cd 100644
--- a/core/lib/include/rmutex.h
+++ b/core/lib/include/rmutex.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @defgroup    core_sync_rmutex Recursive Mutex
  * @ingroup     core_sync
@@ -20,9 +22,6 @@
  *
  */
 
-#ifndef RMUTEX_H
-#define RMUTEX_H
-
 #include <stdint.h>
 
 #include "mutex.h"
@@ -109,5 +108,4 @@ void rmutex_unlock(rmutex_t *rmutex);
 }
 #endif
 
-#endif /* RMUTEX_H */
 /** @} */
diff --git a/core/lib/include/thread_config.h b/core/lib/include/thread_config.h
index d3f3542d95..c9f7a99858 100644
--- a/core/lib/include/thread_config.h
+++ b/core/lib/include/thread_config.h
@@ -8,6 +8,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_thread
  *
@@ -19,9 +21,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef THREAD_CONFIG_H
-#define THREAD_CONFIG_H
-
 #include "cpu_conf.h"
 #include "sched.h"      /* for SCHED_PRIO_LEVELS */
 
@@ -140,5 +139,4 @@ extern "C" {
 }
 #endif
 
-#endif /* THREAD_CONFIG_H */
 /** @} */
diff --git a/core/lib/include/xfa.h b/core/lib/include/xfa.h
index e18196ff78..726674dbe9 100644
--- a/core/lib/include/xfa.h
+++ b/core/lib/include/xfa.h
@@ -6,6 +6,8 @@
  * directory for more details.
  */
 
+#pragma once
+
 /**
  * @ingroup     core_util
  * @brief       Cross File Arrays
@@ -22,9 +24,6 @@
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
  */
 
-#ifndef XFA_H
-#define XFA_H
-
 #include <inttypes.h>
 #include "compiler_hints.h"
 
@@ -194,5 +193,4 @@ extern "C" {
 }
 #endif
 
-#endif /* XFA_H */
 /** @} */