diff --git a/include/SDL3/SDL_begin_code.h b/include/SDL3/SDL_begin_code.h
index 0bebddde5e1fe..82aa3e817942f 100644
--- a/include/SDL3/SDL_begin_code.h
+++ b/include/SDL3/SDL_begin_code.h
@@ -28,10 +28,10 @@
  */
 
 /* This shouldn't be nested -- included it around code only. */
-#ifdef _SDL_begin_code_h
+#ifdef SDL_begin_code_h
 #error Nested inclusion of SDL_begin_code.h
 #endif
-#define _SDL_begin_code_h
+#define SDL_begin_code_h
 
 #ifndef SDL_DEPRECATED
 #  if defined(__GNUC__) && (__GNUC__ >= 4)  /* technically, this arrived in gcc 3.1, but oh well. */
diff --git a/include/SDL3/SDL_close_code.h b/include/SDL3/SDL_close_code.h
index 7ebccc81d95d7..201d791c24a7e 100644
--- a/include/SDL3/SDL_close_code.h
+++ b/include/SDL3/SDL_close_code.h
@@ -26,10 +26,10 @@
  *  after you finish any function and structure declarations in your headers
  */
 
-#ifndef _SDL_begin_code_h
+#ifndef SDL_begin_code_h
 #error SDL_close_code.h included without matching SDL_begin_code.h
 #endif
-#undef _SDL_begin_code_h
+#undef SDL_begin_code_h
 
 /* Reset structure packing at previous byte alignment */
 #if defined(_MSC_VER) || defined(__MWERKS__) || defined(__BORLANDC__)
diff --git a/include/SDL3/SDL_locale.h b/include/SDL3/SDL_locale.h
index 416d64b028d8d..49c1a1289890e 100644
--- a/include/SDL3/SDL_locale.h
+++ b/include/SDL3/SDL_locale.h
@@ -25,8 +25,8 @@
  *  Include file for SDL locale services
  */
 
-#ifndef _SDL_locale_h
-#define _SDL_locale_h
+#ifndef SDL_locale_h
+#define SDL_locale_h
 
 #include <SDL3/SDL_stdinc.h>
 #include <SDL3/SDL_error.h>
@@ -98,4 +98,4 @@ extern DECLSPEC SDL_Locale * SDLCALL SDL_GetPreferredLocales(void);
 #endif
 #include <SDL3/SDL_close_code.h>
 
-#endif /* _SDL_locale_h */
+#endif /* SDL_locale_h */
diff --git a/include/build_config/SDL_build_config_emscripten.h b/include/build_config/SDL_build_config_emscripten.h
index 289caeb67ac66..b415749354373 100644
--- a/include/build_config/SDL_build_config_emscripten.h
+++ b/include/build_config/SDL_build_config_emscripten.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_build_config_emscripten_h_
-#define _SDL_build_config_emscripten_h_
+#ifndef SDL_build_config_emscripten_h
+#define SDL_build_config_emscripten_h
 
 #include <SDL3/SDL_platform.h>
 
@@ -210,4 +210,4 @@
 /* Enable system filesystem support */
 #define SDL_FILESYSTEM_EMSCRIPTEN 1
 
-#endif /* _SDL_build_config_emscripten_h_ */
+#endif /* SDL_build_config_emscripten_h */
diff --git a/src/audio/aaudio/SDL_aaudio.h b/src/audio/aaudio/SDL_aaudio.h
index 50f07cf37b1e4..2740f6f1dcd70 100644
--- a/src/audio/aaudio/SDL_aaudio.h
+++ b/src/audio/aaudio/SDL_aaudio.h
@@ -20,8 +20,8 @@
 */
 #include "SDL_internal.h"
 
-#ifndef _SDL_aaudio_h
-#define _SDL_aaudio_h
+#ifndef SDL_aaudio_h
+#define SDL_aaudio_h
 
 #include "../SDL_sysaudio.h"
 #include <stdbool.h>
@@ -47,4 +47,4 @@ void aaudio_ResumeDevices(void);
 void aaudio_PauseDevices(void);
 SDL_bool aaudio_DetectBrokenPlayState(void);
 
-#endif /* _SDL_aaudio_h */
+#endif /* SDL_aaudio_h */
diff --git a/src/audio/n3ds/SDL_n3dsaudio.h b/src/audio/n3ds/SDL_n3dsaudio.h
index 0b33f0055928d..32be1601b4bb0 100644
--- a/src/audio/n3ds/SDL_n3dsaudio.h
+++ b/src/audio/n3ds/SDL_n3dsaudio.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_n3dsaudio_h_
-#define _SDL_n3dsaudio_h_
+#ifndef SDL_n3dsaudio_h
+#define SDL_n3dsaudio_h
 
 #include <3ds.h>
 
@@ -46,4 +46,4 @@ struct SDL_PrivateAudioData
     SDL_bool isCancelled;
 };
 
-#endif /* _SDL_n3dsaudio_h_ */
+#endif /* SDL_n3dsaudio_h */
diff --git a/src/audio/openslES/SDL_openslES.h b/src/audio/openslES/SDL_openslES.h
index 56f8376ba23e5..741264bb500c8 100644
--- a/src/audio/openslES/SDL_openslES.h
+++ b/src/audio/openslES/SDL_openslES.h
@@ -20,8 +20,8 @@
 */
 #include "SDL_internal.h"
 
-#ifndef _SDL_openslesaudio_h
-#define _SDL_openslesaudio_h
+#ifndef SDL_openslesaudio_h
+#define SDL_openslesaudio_h
 
 #include "../SDL_sysaudio.h"
 
@@ -41,4 +41,4 @@ struct SDL_PrivateAudioData
 void openslES_ResumeDevices(void);
 void openslES_PauseDevices(void);
 
-#endif /* _SDL_openslesaudio_h */
+#endif /* SDL_openslesaudio_h */
diff --git a/src/audio/vita/SDL_vitaaudio.h b/src/audio/vita/SDL_vitaaudio.h
index 190ff80fbcb82..195a2c132a1c2 100644
--- a/src/audio/vita/SDL_vitaaudio.h
+++ b/src/audio/vita/SDL_vitaaudio.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_vitaaudio_h
-#define _SDL_vitaaudio_h
+#ifndef SDL_vitaaudio_h
+#define SDL_vitaaudio_h
 
 #include "../SDL_sysaudio.h"
 
@@ -41,4 +41,4 @@ struct SDL_PrivateAudioData
     int next_buffer;
 };
 
-#endif /* _SDL_vitaaudio_h */
+#endif /* SDL_vitaaudio_h */
diff --git a/src/video/kmsdrm/SDL_kmsdrmvideo.h b/src/video/kmsdrm/SDL_kmsdrmvideo.h
index 46469014596fb..9191ba68c2ff9 100644
--- a/src/video/kmsdrm/SDL_kmsdrmvideo.h
+++ b/src/video/kmsdrm/SDL_kmsdrmvideo.h
@@ -21,8 +21,8 @@
 
 #include "SDL_internal.h"
 
-#ifndef __SDL_KMSDRMVIDEO_H__
-#define __SDL_KMSDRMVIDEO_H__
+#ifndef SDL_kmsdrmvideo_h
+#define SDL_kmsdrmvideo_h
 
 #include "../SDL_sysvideo.h"
 
@@ -150,4 +150,4 @@ int KMSDRM_GLES_GetSwapInterval(_THIS);
 int KMSDRM_GLES_SwapWindow(_THIS, SDL_Window *window);
 void KMSDRM_GLES_DeleteContext(_THIS, SDL_GLContext context);
 
-#endif /* __SDL_KMSDRMVIDEO_H__ */
+#endif /* SDL_kmsdrmvideo_h */
diff --git a/src/video/ngage/SDL_ngagevideo.h b/src/video/ngage/SDL_ngagevideo.h
index ff91012bc2b31..5bda458416717 100644
--- a/src/video/ngage/SDL_ngagevideo.h
+++ b/src/video/ngage/SDL_ngagevideo.h
@@ -21,8 +21,8 @@
 
 #include "SDL_internal.h"
 
-#ifndef _SDL_ngagevideo_h
-#define _SDL_ngagevideo_h
+#ifndef SDL_ngagevideo_h
+#define SDL_ngagevideo_h
 
 #include "../SDL_sysvideo.h"
 
@@ -63,4 +63,4 @@ typedef struct SDL_VideoData
 
 } SDL_VideoData;
 
-#endif /* _SDL_ngagevideo_h */
+#endif /* SDL_ngagevideo_h */
diff --git a/src/video/ngage/SDL_ngagewindow.h b/src/video/ngage/SDL_ngagewindow.h
index cb69faaebf36c..a1f4f5813f9e1 100644
--- a/src/video/ngage/SDL_ngagewindow.h
+++ b/src/video/ngage/SDL_ngagewindow.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_ngagewindow_h
-#define _SDL_ngagewindow_h
+#ifndef SDL_ngagewindow_h
+#define SDL_ngagewindow_h
 
 #include "../SDL_sysvideo.h"
 
@@ -40,4 +40,4 @@ NGAGE_CreateWindow(_THIS, SDL_Window *window);
 extern void
 NGAGE_DestroyWindow(_THIS, SDL_Window *window);
 
-#endif /* _SDL_ngagewindow */
+#endif /* SDL_ngagewindow */
diff --git a/src/video/offscreen/SDL_offscreenopengles.h b/src/video/offscreen/SDL_offscreenopengles.h
index 26c52b45ffb79..ed9901aef3974 100644
--- a/src/video/offscreen/SDL_offscreenopengles.h
+++ b/src/video/offscreen/SDL_offscreenopengles.h
@@ -20,8 +20,8 @@
 */
 #include "SDL_internal.h"
 
-#ifndef _SDL_offscreenopengles_h
-#define _SDL_offscreenopengles_h
+#ifndef SDL_offscreenopengles_h
+#define SDL_offscreenopengles_h
 
 #if SDL_VIDEO_DRIVER_OFFSCREEN && SDL_VIDEO_OPENGL_EGL
 
@@ -41,4 +41,4 @@ extern int OFFSCREEN_GLES_SwapWindow(_THIS, SDL_Window *window);
 
 #endif /* SDL_VIDEO_DRIVER_OFFSCREEN && SDL_VIDEO_OPENGL_EGL */
 
-#endif /* _SDL_offscreenopengles_h */
+#endif /* SDL_offscreenopengles_h */
diff --git a/src/video/offscreen/SDL_offscreenvideo.h b/src/video/offscreen/SDL_offscreenvideo.h
index 436152e5f13f2..be4ce825c44d4 100644
--- a/src/video/offscreen/SDL_offscreenvideo.h
+++ b/src/video/offscreen/SDL_offscreenvideo.h
@@ -20,9 +20,9 @@
 */
 #include "SDL_internal.h"
 
-#ifndef _SDL_offscreenvideo_h
-#define _SDL_offscreenvideo_h
+#ifndef SDL_offscreenvideo_h
+#define SDL_offscreenvideo_h
 
 #include "../SDL_sysvideo.h"
 
-#endif /* _SDL_offscreenvideo_h */
+#endif /* SDL_offscreenvideo_h */
diff --git a/src/video/offscreen/SDL_offscreenwindow.h b/src/video/offscreen/SDL_offscreenwindow.h
index 8d5588ec6ca46..8beb84de8cfbf 100644
--- a/src/video/offscreen/SDL_offscreenwindow.h
+++ b/src/video/offscreen/SDL_offscreenwindow.h
@@ -20,8 +20,8 @@
 */
 #include "SDL_internal.h"
 
-#ifndef _SDL_offscreenwindow_h
-#define _SDL_offscreenwindow_h
+#ifndef SDL_offscreenwindow_h
+#define SDL_offscreenwindow_h
 
 #include "SDL_offscreenvideo.h"
 
@@ -37,4 +37,4 @@ typedef struct
 extern int OFFSCREEN_CreateWindow(_THIS, SDL_Window *window);
 extern void OFFSCREEN_DestroyWindow(_THIS, SDL_Window *window);
 
-#endif /* _SDL_offscreenwindow */
+#endif /* SDL_offscreenwindow_h */
diff --git a/src/video/raspberry/SDL_rpivideo.h b/src/video/raspberry/SDL_rpivideo.h
index 40c9552a43611..45050ba99982a 100644
--- a/src/video/raspberry/SDL_rpivideo.h
+++ b/src/video/raspberry/SDL_rpivideo.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef __SDL_RPIVIDEO_H__
-#define __SDL_RPIVIDEO_H__
+#ifndef SDL_rpivideo_h
+#define SDL_rpivideo_h
 
 #include "SDL_internal.h"
 #include "../SDL_sysvideo.h"
@@ -91,4 +91,4 @@ int RPI_GLES_GetSwapInterval(_THIS);
 int RPI_GLES_SwapWindow(_THIS, SDL_Window *window);
 void RPI_GLES_DeleteContext(_THIS, SDL_GLContext context);
 
-#endif /* __SDL_RPIVIDEO_H__ */
+#endif /* SDL_rpivideo_h */
diff --git a/src/video/vita/SDL_vitakeyboard.h b/src/video/vita/SDL_vitakeyboard.h
index bb96426e538e7..f6c810f8e6d21 100644
--- a/src/video/vita/SDL_vitakeyboard.h
+++ b/src/video/vita/SDL_vitakeyboard.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_vitakeyboard_h
-#define _SDL_vitakeyboard_h
+#ifndef SDL_vitakeyboard_h
+#define SDL_vitakeyboard_h
 
 #include "SDL_internal.h"
 
@@ -28,4 +28,4 @@
 extern void VITA_InitKeyboard(void);
 extern void VITA_PollKeyboard(void);
 
-#endif /* _SDL_vitakeyboard_h */
+#endif /* SDL_vitakeyboard_h */
diff --git a/src/video/vita/SDL_vitamouse_c.h b/src/video/vita/SDL_vitamouse_c.h
index ff71a8caea9d9..849afaa7152a1 100644
--- a/src/video/vita/SDL_vitamouse_c.h
+++ b/src/video/vita/SDL_vitamouse_c.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_vitamouse_h
-#define _SDL_vitamouse_h
+#ifndef SDL_vitamouse_h
+#define SDL_vitamouse_h
 
 #include "SDL_internal.h"
 
@@ -28,4 +28,4 @@
 extern void VITA_InitMouse(void);
 extern void VITA_PollMouse(void);
 
-#endif /* _SDL_vitamouse_h */
+#endif /* SDL_vitamouse_h */
diff --git a/src/video/vita/SDL_vitatouch.h b/src/video/vita/SDL_vitatouch.h
index eb47b3cf9e3c4..482a077e5f03d 100644
--- a/src/video/vita/SDL_vitatouch.h
+++ b/src/video/vita/SDL_vitatouch.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_vitatouch_h
-#define _SDL_vitatouch_h
+#ifndef SDL_vitatouch_h
+#define SDL_vitatouch_h
 
 #include "SDL_internal.h"
 
@@ -30,4 +30,4 @@ extern void VITA_QuitTouch(void);
 extern void VITA_PollTouch(void);
 void VITA_ConvertTouchXYToSDLXY(float *sdl_x, float *sdl_y, int vita_x, int vita_y, int port);
 
-#endif /* _SDL_vitatouch_h */
+#endif /* SDL_vitatouch_h */
diff --git a/src/video/vita/SDL_vitavideo.h b/src/video/vita/SDL_vitavideo.h
index 575dc8f0404ce..ffe8522a47b84 100644
--- a/src/video/vita/SDL_vitavideo.h
+++ b/src/video/vita/SDL_vitavideo.h
@@ -19,8 +19,8 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
-#ifndef _SDL_vitavideo_h
-#define _SDL_vitavideo_h
+#ifndef SDL_vitavideo_h
+#define SDL_vitavideo_h
 
 #include "SDL_internal.h"
 #include "../SDL_sysvideo.h"
@@ -110,4 +110,4 @@ SDL_bool VITA_IsScreenKeyboardShown(_THIS, SDL_Window *window);
 
 void VITA_PumpEvents(_THIS);
 
-#endif /* _SDL_pspvideo_h */
+#endif /* SDL_pspvideo_h */