diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index e0a9c75354..d4032a39fb 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -1,5 +1,5 @@
-#ifndef __CONFIGURATION_H
-#define __CONFIGURATION_H
+#ifndef CONFIGURATION_H
+#define CONFIGURATION_H
 
 // This configurtion file contains the basic settings.
 // Advanced settings can be found in Configuration_adv.h 
diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index 8a817c13ed..0d1e914ad3 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -1,5 +1,5 @@
-#ifndef __CONFIGURATION_ADV_H
-#define __CONFIGURATION_ADV_H
+#ifndef CONFIGURATION_ADV_H
+#define CONFIGURATION_ADV_H
 
 //===========================================================================
 //=============================Thermal Settings  ============================
diff --git a/Marlin/EEPROMwrite.h b/Marlin/EEPROMwrite.h
index d639e56399..96e2ec9856 100644
--- a/Marlin/EEPROMwrite.h
+++ b/Marlin/EEPROMwrite.h
@@ -1,5 +1,5 @@
-#ifndef __EEPROMH
-#define __EEPROMH
+#ifndef EEPROM_H
+#define EEPROM_H
 
 #include "Marlin.h"
 #include "planner.h"
diff --git a/Marlin/Marlin.h b/Marlin/Marlin.h
index 5bb728c6fa..4123634442 100644
--- a/Marlin/Marlin.h
+++ b/Marlin/Marlin.h
@@ -1,8 +1,8 @@
 // Tonokip RepRap firmware rewrite based off of Hydra-mmm firmware.
 // Licence: GPL
 
-#ifndef __MARLINH
-#define __MARLINH
+#ifndef MARLIN_H
+#define MARLIN_H
 
 #define  HardwareSerial_h // trick to disable the standard HWserial
 
diff --git a/Marlin/cardreader.h b/Marlin/cardreader.h
index 5c6e29ad81..964bbe7669 100644
--- a/Marlin/cardreader.h
+++ b/Marlin/cardreader.h
@@ -1,5 +1,5 @@
-#ifndef __CARDREADERH
-#define __CARDREADERH
+#ifndef CARDREADER_H
+#define CARDREADER_H
 
 #ifdef SDSUPPORT
 
diff --git a/Marlin/ultralcd.h b/Marlin/ultralcd.h
index f62662a6d0..dc44d1cda9 100644
--- a/Marlin/ultralcd.h
+++ b/Marlin/ultralcd.h
@@ -1,5 +1,5 @@
-#ifndef __ULTRALCDH
-#define __ULTRALCDH
+#ifndef ULTRALCD_H
+#define ULTRALCD_H
 #include "Marlin.h"
 #ifdef ULTRA_LCD
   #include <LiquidCrystal.h>
diff --git a/Marlin/watchdog.h b/Marlin/watchdog.h
index ff6af60afd..937379b696 100644
--- a/Marlin/watchdog.h
+++ b/Marlin/watchdog.h
@@ -1,5 +1,5 @@
-#ifndef __WATCHDOGH
-#define __WATCHDOGH
+#ifndef WATCHDOG_H
+#define WATCHDOG_H
 #include "Marlin.h"
 #ifdef USE_WATCHDOG