diff --git a/modules/gimpcolorwheel.h b/modules/gimpcolorwheel.h
index b5ebece36d..7220d81e2f 100644
--- a/modules/gimpcolorwheel.h
+++ b/modules/gimpcolorwheel.h
@@ -27,8 +27,7 @@
  * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
  */
 
-#ifndef __GIMP_COLOR_WHEEL_H__
-#define __GIMP_COLOR_WHEEL_H__
+#pragma once
 
 G_BEGIN_DECLS
 
@@ -93,5 +92,3 @@ void        gimp_color_wheel_set_color_config  (GimpColorWheel  *wheel,
 gboolean    gimp_color_wheel_is_adjusting      (GimpColorWheel  *wheel);
 
 G_END_DECLS
-
-#endif /* __GIMP_COLOR_WHEEL_H__ */
diff --git a/modules/gimpinputdevicestore.h b/modules/gimpinputdevicestore.h
index a02d453c07..905406aeb8 100644
--- a/modules/gimpinputdevicestore.h
+++ b/modules/gimpinputdevicestore.h
@@ -18,8 +18,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#ifndef __GIMP_INPUT_DEVICE_STORE_H__
-#define __GIMP_INPUT_DEVICE_STORE_H__
+#pragma once
 
 
 #define GIMP_TYPE_INPUT_DEVICE_STORE    (gimp_input_device_store_get_type ())
@@ -37,6 +36,3 @@ GimpInputDeviceStore * gimp_input_device_store_new             (void);
 gchar                * gimp_input_device_store_get_device_file (GimpInputDeviceStore  *store,
                                                                 const gchar           *udi);
 GError               * gimp_input_device_store_get_error       (GimpInputDeviceStore  *store);
-
-
-#endif  /* __GIMP_INPUT_DEVICE_STORE_H__ */
diff --git a/tools/generate-welcome-dialog-data.py b/tools/generate-welcome-dialog-data.py
index 22d8a3f96f..db8e05feb1 100755
--- a/tools/generate-welcome-dialog-data.py
+++ b/tools/generate-welcome-dialog-data.py
@@ -115,8 +115,7 @@ if __name__ == "__main__":
   intro_p, items, demos = parse_appdata(infile, args.version)
 
   if args.header:
-    print('#ifndef __WELCOME_DIALOG_DATA_H__')
-    print('#define __WELCOME_DIALOG_DATA_H__\n\n')
+    print('#pragma once\n\n')
 
     print('extern gint          gimp_welcome_dialog_n_items;')
     print('extern const gchar * gimp_welcome_dialog_items[];')
@@ -125,7 +124,6 @@ if __name__ == "__main__":
     print('extern gint          gimp_welcome_dialog_intro_n_paragraphs;')
     print('extern const gchar * gimp_welcome_dialog_intro[];')
 
-    print('\n\n#endif /* __WELCOME_DIALOG_DATA_H__ */')
   else:
     print('#include "config.h"')
     print('#include <glib.h>')
diff --git a/tools/kernelgen.c b/tools/kernelgen.c
index e2d8ef068a..c03971462c 100644
--- a/tools/kernelgen.c
+++ b/tools/kernelgen.c
@@ -91,8 +91,7 @@ main (int    argc,
           " *   This file was generated using kernelgen as found in the tools dir.\n");
   printf (" *   (threshold = %g)\n", THRESHOLD);
   printf (" */\n\n");
-  printf ("#ifndef __GIMP_BRUSH_CORE_KERNELS_H__\n");
-  printf ("#define __GIMP_BRUSH_CORE_KERNELS_H__\n\n");
+  printf ("#pragma once\n\n");
   printf ("#define KERNEL_WIDTH     %d\n", KERNEL_WIDTH);
   printf ("#define KERNEL_HEIGHT    %d\n", KERNEL_HEIGHT);
   printf ("#define KERNEL_SUBSAMPLE %d\n", SUBSAMPLE);
@@ -120,9 +119,7 @@ main (int    argc,
       printf ("  }%s", j < SUBSAMPLE ? ",\n" : "\n");
     }
 
-  printf ("};\n\n");
-
-  printf ("#endif /* __GIMP_BRUSH_CORE_KERNELS_H__ */\n");
+  printf ("};\n");
 
   return 0;
 }