diff --git a/libraries/AP_HAL_PX4/AP_HAL_PX4.h b/libraries/AP_HAL_PX4/AP_HAL_PX4.h
index fa5cc6fcd8..332a91ff38 100644
--- a/libraries/AP_HAL_PX4/AP_HAL_PX4.h
+++ b/libraries/AP_HAL_PX4/AP_HAL_PX4.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_H__
-#define __AP_HAL_PX4_H__
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 
@@ -8,5 +6,3 @@
 #include "HAL_PX4_Class.h"
 
 #endif // CONFIG_HAL_BOARD
-#endif // __AP_HAL_PX4_H__
-
diff --git a/libraries/AP_HAL_PX4/AP_HAL_PX4_Namespace.h b/libraries/AP_HAL_PX4/AP_HAL_PX4_Namespace.h
index b55fe12216..1642b466a6 100644
--- a/libraries/AP_HAL_PX4/AP_HAL_PX4_Namespace.h
+++ b/libraries/AP_HAL_PX4/AP_HAL_PX4_Namespace.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_NAMESPACE_H__
-#define __AP_HAL_PX4_NAMESPACE_H__
+#pragma once
 
 namespace PX4 {
 	class PX4Scheduler;
@@ -18,6 +16,3 @@ namespace PX4 {
         class PX4_I2C;
         class Semaphore;
 }
-
-#endif //__AP_HAL_PX4_NAMESPACE_H__
-
diff --git a/libraries/AP_HAL_PX4/AnalogIn.h b/libraries/AP_HAL_PX4/AnalogIn.h
index 657c2707c8..c52ea0b6ec 100644
--- a/libraries/AP_HAL_PX4/AnalogIn.h
+++ b/libraries/AP_HAL_PX4/AnalogIn.h
@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef __AP_HAL_PX4_ANALOGIN_H__
-#define __AP_HAL_PX4_ANALOGIN_H__
+#pragma once
 
 #include "AP_HAL_PX4.h"
 #include <pthread.h>
@@ -82,4 +80,3 @@ private:
 
     void next_stop_pin(void);
 };
-#endif // __AP_HAL_PX4_ANALOGIN_H__
diff --git a/libraries/AP_HAL_PX4/GPIO.h b/libraries/AP_HAL_PX4/GPIO.h
index 59fbcdbc8b..21461accdf 100644
--- a/libraries/AP_HAL_PX4/GPIO.h
+++ b/libraries/AP_HAL_PX4/GPIO.h
@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef __AP_HAL_PX4_GPIO_H__
-#define __AP_HAL_PX4_GPIO_H__
+#pragma once
 
 #include "AP_HAL_PX4.h"
 
@@ -67,5 +65,3 @@ public:
 private:
     uint8_t _v;
 };
-
-#endif // __AP_HAL_PX4_GPIO_H__
diff --git a/libraries/AP_HAL_PX4/I2CDriver.h b/libraries/AP_HAL_PX4/I2CDriver.h
index 5c579d9b12..f7039e5434 100644
--- a/libraries/AP_HAL_PX4/I2CDriver.h
+++ b/libraries/AP_HAL_PX4/I2CDriver.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_I2CDRIVER_H__
-#define __AP_HAL_PX4_I2CDRIVER_H__
+#pragma once
 
 #include "AP_HAL_PX4.h"
 #include <AP_HAL_Empty/AP_HAL_Empty.h>
@@ -47,5 +45,3 @@ private:
     Empty::Semaphore semaphore;
     PX4_I2C *px4_i2c = nullptr;
 };
-
-#endif // __AP_HAL_PX4_I2CDRIVER_H__
diff --git a/libraries/AP_HAL_PX4/RCInput.h b/libraries/AP_HAL_PX4/RCInput.h
index 7cdd0301a8..e8282994ad 100644
--- a/libraries/AP_HAL_PX4/RCInput.h
+++ b/libraries/AP_HAL_PX4/RCInput.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_RCINPUT_H__
-#define __AP_HAL_PX4_RCINPUT_H__
+#pragma once
 
 #include "AP_HAL_PX4.h"
 #include <drivers/drv_rc_input.h>
@@ -38,5 +36,3 @@ private:
     perf_counter_t _perf_rcin;
     pthread_mutex_t rcin_mutex;
 };
-
-#endif // __AP_HAL_PX4_RCINPUT_H__
diff --git a/libraries/AP_HAL_PX4/RCOutput.h b/libraries/AP_HAL_PX4/RCOutput.h
index 35899c1cd7..94b762b60a 100644
--- a/libraries/AP_HAL_PX4/RCOutput.h
+++ b/libraries/AP_HAL_PX4/RCOutput.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_RCOUTPUT_H__
-#define __AP_HAL_PX4_RCOUTPUT_H__
+#pragma once
 
 #include "AP_HAL_PX4.h"
 #include <systemlib/perf_counter.h>
@@ -63,5 +61,3 @@ private:
     void _arm_actuators(bool arm);
     void set_freq_fd(int fd, uint32_t chmask, uint16_t freq_hz);
 };
-
-#endif // __AP_HAL_PX4_RCOUTPUT_H__
diff --git a/libraries/AP_HAL_PX4/Scheduler.h b/libraries/AP_HAL_PX4/Scheduler.h
index da7ec90dae..c242352ff8 100644
--- a/libraries/AP_HAL_PX4/Scheduler.h
+++ b/libraries/AP_HAL_PX4/Scheduler.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_SCHEDULER_H__
-#define __AP_HAL_PX4_SCHEDULER_H__
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 #if CONFIG_HAL_BOARD == HAL_BOARD_PX4
@@ -102,6 +100,3 @@ private:
     perf_counter_t  _perf_delay;
 };
 #endif
-#endif // __AP_HAL_PX4_SCHEDULER_H__
-
-
diff --git a/libraries/AP_HAL_PX4/Storage.h b/libraries/AP_HAL_PX4/Storage.h
index 01ae7d9e05..e97dbdc7f5 100644
--- a/libraries/AP_HAL_PX4/Storage.h
+++ b/libraries/AP_HAL_PX4/Storage.h
@@ -1,7 +1,4 @@
-
-
-#ifndef __AP_HAL_PX4_STORAGE_H__
-#define __AP_HAL_PX4_STORAGE_H__
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 #include "AP_HAL_PX4_Namespace.h"
@@ -43,5 +40,3 @@ private:
 #endif
     void bus_lock(bool lock);
 };
-
-#endif // __AP_HAL_PX4_STORAGE_H__
diff --git a/libraries/AP_HAL_PX4/UARTDriver.h b/libraries/AP_HAL_PX4/UARTDriver.h
index bdde1b1ac0..73924ad203 100644
--- a/libraries/AP_HAL_PX4/UARTDriver.h
+++ b/libraries/AP_HAL_PX4/UARTDriver.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_UARTDRIVER_H__
-#define __AP_HAL_PX4_UARTDRIVER_H__
+#pragma once
 
 #include "AP_HAL_PX4.h"
 #include <systemlib/perf_counter.h>
@@ -80,5 +78,3 @@ private:
     pid_t _uart_owner_pid;
 
 };
-
-#endif // __AP_HAL_PX4_UARTDRIVER_H__
diff --git a/libraries/AP_HAL_PX4/Util.h b/libraries/AP_HAL_PX4/Util.h
index f5583ae495..801858347e 100644
--- a/libraries/AP_HAL_PX4/Util.h
+++ b/libraries/AP_HAL_PX4/Util.h
@@ -1,6 +1,4 @@
-
-#ifndef __AP_HAL_PX4_UTIL_H__
-#define __AP_HAL_PX4_UTIL_H__
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 #include "AP_HAL_PX4_Namespace.h"
@@ -64,5 +62,3 @@ private:
     int _safety_handle;
     PX4::NSHShellStream _shell_stream;
 };
-
-#endif // __AP_HAL_PX4_UTIL_H__