diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 4720e4e878..a61ca947aa 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -623,7 +623,7 @@
 
 #if ENABLED(PIDTEMP)
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
-                                  // Set/get with gcode: M301 E[extruder number, 0-2]
+                                  // Set/get with G-code: M301 E[extruder number, 0-2]
 
   #if ENABLED(PID_PARAMS_PER_HOTEND)
     // Specify up to one value per hotend here, according to your setup.
diff --git a/Marlin/Makefile b/Marlin/Makefile
index f1c89ff7f5..417c979f88 100644
--- a/Marlin/Makefile
+++ b/Marlin/Makefile
@@ -512,7 +512,7 @@ else ifeq ($(HARDWARE_MOTHERBOARD),1324)
 else ifeq ($(HARDWARE_MOTHERBOARD),1325)
 # Intamsys 4.0 (Funmat HT)
 else ifeq ($(HARDWARE_MOTHERBOARD),1326)
-# Malyan M180 Mainboard Version 2 (no display function, direct gcode only)
+# Malyan M180 Mainboard Version 2 (no display function, direct G-code only)
 else ifeq ($(HARDWARE_MOTHERBOARD),1327)
 # Geeetech GT2560 Rev B for A20(M/T/D)
 else ifeq ($(HARDWARE_MOTHERBOARD),1328)
diff --git a/Marlin/src/core/boards.h b/Marlin/src/core/boards.h
index 5b0210d9e4..ef750056d6 100644
--- a/Marlin/src/core/boards.h
+++ b/Marlin/src/core/boards.h
@@ -161,7 +161,7 @@
 #define BOARD_PICA_REVB               1324  // PICA Shield (original version)
 #define BOARD_PICA                    1325  // PICA Shield (rev C or later)
 #define BOARD_INTAMSYS40              1326  // Intamsys 4.0 (Funmat HT)
-#define BOARD_MALYAN_M180             1327  // Malyan M180 Mainboard Version 2 (no display function, direct gcode only)
+#define BOARD_MALYAN_M180             1327  // Malyan M180 Mainboard Version 2 (no display function, direct G-code only)
 #define BOARD_GT2560_V4_A20           1328  // Geeetech GT2560 Rev B for A20(M/T/D)
 #define BOARD_PROTONEER_CNC_SHIELD_V3 1329  // Mega controller & Protoneer CNC Shield V3.00
 #define BOARD_WEEDO_62A               1330  // WEEDO 62A board (TINA2, Monoprice Cadet, etc.)
diff --git a/Marlin/src/feature/meatpack.cpp b/Marlin/src/feature/meatpack.cpp
index b2899243b2..07ff41e5be 100644
--- a/Marlin/src/feature/meatpack.cpp
+++ b/Marlin/src/feature/meatpack.cpp
@@ -26,7 +26,7 @@
  * Algorithm & Implementation: Scott Mudge - mail@scottmudge.com
  * Date: Dec. 2020
  *
- * Character Frequencies from ~30 MB of comment-stripped gcode:
+ * Character Frequencies from ~30 MB of comment-stripped G-code:
  *  '1' -> 4451136    '4' -> 1353273   '\n' -> 1087683    '-' ->   90242
  *  '0' -> 4253577    '9' -> 1352147    'G' -> 1075806    'Z' ->   34109
  *  ' ' -> 3053297    '3' -> 1262929    'X' ->  975742    'M' ->   11879
diff --git a/Marlin/src/feature/meatpack.h b/Marlin/src/feature/meatpack.h
index a56e65b6cc..98a535e592 100644
--- a/Marlin/src/feature/meatpack.h
+++ b/Marlin/src/feature/meatpack.h
@@ -29,7 +29,7 @@
  * Specifically optimized for 3D printing G-Code, this is a zero-cost data compression method
  * which packs ~180-190% more data into the same amount of bytes going to the CNC controller.
  * As a majority of G-Code can be represented by a restricted alphabet, I performed histogram
- * analysis on a wide variety of 3D printing gcode samples, and found ~93% of all gcode could
+ * analysis on a wide variety of 3D printing G-code samples, and found ~93% of all G-code could
  * be represented by the same 15-character alphabet.
  *
  * This allowed me to design a system of packing 2 8-bit characters into a single byte, assuming
@@ -38,7 +38,7 @@
  *
  * Combined with some logic to allow commingling of full-width characters outside of this 15-
  * character alphabet (at the cost of an extra 8-bits per full-width character), and by stripping
- * out unnecessary comments, the end result is gcode which is roughly half the original size.
+ * out unnecessary comments, the end result is G-code which is roughly half the original size.
  *
  * Why did I do this? I noticed micro-stuttering and other data-bottleneck issues while printing
  * objects with high curvature, especially at high speeds. There is also the issue of the limited
diff --git a/Marlin/src/feature/mmu/mmu2-serial-protocol.md b/Marlin/src/feature/mmu/mmu2-serial-protocol.md
index 7ff0901742..93135e406f 100644
--- a/Marlin/src/feature/mmu/mmu2-serial-protocol.md
+++ b/Marlin/src/feature/mmu/mmu2-serial-protocol.md
@@ -51,7 +51,7 @@ When done, the MMU sends
 
 - MMU => 'ok\n'
 
-We don't wait for a response here but immediately continue with the next gcode which should
+We don't wait for a response here but immediately continue with the next G-code which should
 be one or more extruder moves to feed the filament into the hotend.
 
 
diff --git a/Marlin/src/feature/mmu/mmu2.cpp b/Marlin/src/feature/mmu/mmu2.cpp
index 2544995c6d..a4718b53d9 100644
--- a/Marlin/src/feature/mmu/mmu2.cpp
+++ b/Marlin/src/feature/mmu/mmu2.cpp
@@ -939,7 +939,7 @@ bool MMU2::load_filament_to_nozzle(const uint8_t index) {
  * Load filament to nozzle of multimaterial printer
  *
  * This function is used only after T? (user select filament) and M600 (change filament).
- * It is not used after T0 .. T4 command (select filament), in such case, gcode is responsible for loading
+ * It is not used after T0 .. T4 command (select filament), in such case, G-code is responsible for loading
  * filament to nozzle.
  */
 void MMU2::load_to_nozzle() {
diff --git a/Marlin/src/gcode/gcode.cpp b/Marlin/src/gcode/gcode.cpp
index 70e2f36f2f..f6e6dda5f8 100644
--- a/Marlin/src/gcode/gcode.cpp
+++ b/Marlin/src/gcode/gcode.cpp
@@ -21,7 +21,7 @@
  */
 
 /**
- * gcode.cpp - Temporary container for all gcode handlers
+ * gcode.cpp - Temporary container for all G-code handlers
  *             Most will migrate to classes, by feature.
  */
 
diff --git a/Marlin/src/gcode/gcode.h b/Marlin/src/gcode/gcode.h
index 772accba5d..509c6e219d 100644
--- a/Marlin/src/gcode/gcode.h
+++ b/Marlin/src/gcode/gcode.h
@@ -110,7 +110,7 @@
  * M33  - Get the longname version of a path. (Requires LONG_FILENAME_HOST_SUPPORT)
  * M34  - Set SD Card sorting options. (Requires SDCARD_SORT_ALPHA)
  *
- * M42  - Change pin status via gcode: M42 P<pin> S<value>. LED pin assumed if P is omitted. (Requires DIRECT_PIN_CONTROL)
+ * M42  - Change pin status via G-code: M42 P<pin> S<value>. LED pin assumed if P is omitted. (Requires DIRECT_PIN_CONTROL)
  * M43  - Display pin status, watch pins for changes, watch endstops & toggle LED, Z servo probe test, toggle pins (Requires PINS_DEBUGGING)
  * M48  - Measure Z Probe repeatability: M48 P<points> X<pos> Y<pos> V<level> E<engage> L<legs> S<chizoid>. (Requires Z_MIN_PROBE_REPEATABILITY_TEST)
  *
diff --git a/Marlin/src/gcode/parser.h b/Marlin/src/gcode/parser.h
index 1487c083ec..a32999f2d2 100644
--- a/Marlin/src/gcode/parser.h
+++ b/Marlin/src/gcode/parser.h
@@ -45,7 +45,7 @@
 /**
  * GCode parser
  *
- *  - Parse a single gcode line for its letter, code, subcode, and parameters
+ *  - Parse a single G-code line for its letter, code, subcode, and parameters
  *  - FASTER_GCODE_PARSER:
  *    - Flags existing params (1 bit each)
  *    - Stores value offsets (1 byte each)
diff --git a/Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.cpp b/Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.cpp
index 7561c89d79..285729cc15 100644
--- a/Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.cpp
+++ b/Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.cpp
@@ -708,7 +708,7 @@ void ChironTFT::PanelAction(uint8_t req) {
       // Old TFT A22 X -1F1500      A22 X +1F1500
       // New TFT A22 X-1.0 F1500    A22 X1.0 F1500
 
-      // lets just wrap this in a gcode relative nonprint move and let the controller deal with it
+      // Send a G-code-relative non-print move and let the controller deal with it
       // G91 G0 <panel command> G90
 
       if (!isPrinting()) { // Ignore request if printing
diff --git a/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp b/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp
index 6fa188bf5f..0eb95bb041 100644
--- a/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp
+++ b/Marlin/src/lcd/extui/dgus/DGUSDisplay.cpp
@@ -243,7 +243,7 @@ void DGUSDisplay::WritePGM(const char str[], uint8_t len) {
 }
 
 void DGUSDisplay::loop() {
-  // protect against recursion… ProcessRx() may indirectly call idle() when injecting gcode commands.
+  // Protect against recursion. ProcessRx() may indirectly call idle() when injecting G-code commands.
   if (!no_reentrance) {
     no_reentrance = true;
     ProcessRx();
diff --git a/Marlin/src/lcd/extui/malyan/malyan.cpp b/Marlin/src/lcd/extui/malyan/malyan.cpp
index df7f305df2..06c9886f01 100644
--- a/Marlin/src/lcd/extui/malyan/malyan.cpp
+++ b/Marlin/src/lcd/extui/malyan/malyan.cpp
@@ -24,7 +24,7 @@
  * lcd/extui/malyan/malyan.cpp
  *
  * LCD implementation for Malyan's LCD, a separate ESP8266 MCU running
- * on Serial1 for the M200 board. This module outputs a pseudo-gcode
+ * on Serial1 for the M200 board. This module outputs a pseudo-G-code
  * wrapped in curly braces which the LCD implementation translates into
  * actual G-code commands.
  *
diff --git a/Marlin/src/lcd/extui/mks_ui/draw_print_file.cpp b/Marlin/src/lcd/extui/mks_ui/draw_print_file.cpp
index 5d6a991910..0199bc1f55 100644
--- a/Marlin/src/lcd/extui/mks_ui/draw_print_file.cpp
+++ b/Marlin/src/lcd/extui/mks_ui/draw_print_file.cpp
@@ -369,7 +369,7 @@ uint32_t lv_open_gcode_file(char *path) {
     card.openFileRead(cur_name);
     card.read(public_buf, 512);
     ps4 = (uint32_t *)strstr((char *)public_buf, ";simage:");
-    // Ignore the beginning message of gcode file
+    // Ignore the beginning message of G-code file
     if (ps4) {
       pre_sread_cnt = (uintptr_t)ps4 - (uintptr_t)((uint32_t *)(&public_buf[0]));
       card.setIndex(pre_sread_cnt);
@@ -490,7 +490,7 @@ void cutFileName(char *path, int len, int bytePerLine, char *outStr) {
                 //&& (strIndex2 != 0) && (strIndex1 < strIndex2)
                 ) ? strIndex1 + 1 : tmpFile;
 
-  if (strIndex2 == 0 || (strIndex1 > strIndex2)) { // not gcode file
+  if (strIndex2 == 0 || (strIndex1 > strIndex2)) { // not G-code file
     #if _LFN_UNICODE
       if (wcslen(beginIndex) > len)
         wcsncpy(outStr, beginIndex, len);
@@ -503,7 +503,7 @@ void cutFileName(char *path, int len, int bytePerLine, char *outStr) {
         strcpy(outStr, beginIndex);
     #endif
   }
-  else { // gcode file
+  else { // G-code file
     if (strIndex2 - beginIndex > (len - 2)) {
       #if _LFN_UNICODE
         wcsncpy(outStr, (const WCHAR *)beginIndex, len - 3);
diff --git a/Marlin/src/lcd/extui/mks_ui/draw_ui.cpp b/Marlin/src/lcd/extui/mks_ui/draw_ui.cpp
index d3f192e44f..6a8333fd66 100644
--- a/Marlin/src/lcd/extui/mks_ui/draw_ui.cpp
+++ b/Marlin/src/lcd/extui/mks_ui/draw_ui.cpp
@@ -159,7 +159,7 @@ void gCfgItems_init() {
     gCfgItems.spi_flash_flag = FLASH_INF_VALID_FLAG;
     W25QXX.SPI_FLASH_SectorErase(VAR_INF_ADDR);
     W25QXX.SPI_FLASH_BufferWrite((uint8_t *)&gCfgItems, VAR_INF_ADDR, sizeof(gCfgItems));
-    // init gcode command
+    // Init G-code command
     W25QXX.SPI_FLASH_BufferWrite((uint8_t *)&custom_gcode_command[0], AUTO_LEVELING_COMMAND_ADDR, 100);
     W25QXX.SPI_FLASH_BufferWrite((uint8_t *)&custom_gcode_command[1], OTHERS_COMMAND_ADDR_1, 100);
     W25QXX.SPI_FLASH_BufferWrite((uint8_t *)&custom_gcode_command[2], OTHERS_COMMAND_ADDR_2, 100);
@@ -238,7 +238,7 @@ void update_spi_flash() {
   uint8_t command_buf[512];
 
   W25QXX.init(SPI_QUARTER_SPEED);
-  // read back the gcode command before erase spi flash
+  // read back the G-code command before erase spi flash
   W25QXX.SPI_FLASH_BufferRead((uint8_t *)&command_buf, GCODE_COMMAND_ADDR, sizeof(command_buf));
   W25QXX.SPI_FLASH_SectorErase(VAR_INF_ADDR);
   W25QXX.SPI_FLASH_BufferWrite((uint8_t *)&gCfgItems, VAR_INF_ADDR, sizeof(gCfgItems));
@@ -249,7 +249,7 @@ void update_gcode_command(int addr, uint8_t *s) {
   uint8_t command_buf[512];
 
   W25QXX.init(SPI_QUARTER_SPEED);
-  // read back the gcode command before erase spi flash
+  // read back the G-code command before erase spi flash
   W25QXX.SPI_FLASH_BufferRead((uint8_t *)&command_buf, GCODE_COMMAND_ADDR, sizeof(command_buf));
   W25QXX.SPI_FLASH_SectorErase(VAR_INF_ADDR);
   W25QXX.SPI_FLASH_BufferWrite((uint8_t *)&gCfgItems, VAR_INF_ADDR, sizeof(gCfgItems));
diff --git a/Marlin/src/lcd/extui/mks_ui/pic_manager.h b/Marlin/src/lcd/extui/mks_ui/pic_manager.h
index 320cb20b0b..cdcc5b76b8 100644
--- a/Marlin/src/lcd/extui/mks_ui/pic_manager.h
+++ b/Marlin/src/lcd/extui/mks_ui/pic_manager.h
@@ -122,7 +122,7 @@
 #define VAR_INF_ADDR                    0x000000
 #define FLASH_INF_VALID_FLAG            0x20201118
 
-// Store some gcode commands, such as auto leveling commands
+// Store some G-code commands, such as auto-leveling commands
 #define GCODE_COMMAND_ADDR              VAR_INF_ADDR + 3 * 1024
 #define AUTO_LEVELING_COMMAND_ADDR      GCODE_COMMAND_ADDR
 #define OTHERS_COMMAND_ADDR_1           AUTO_LEVELING_COMMAND_ADDR + 100
diff --git a/Marlin/src/module/planner.h b/Marlin/src/module/planner.h
index c450418a5c..1af5ccc810 100644
--- a/Marlin/src/module/planner.h
+++ b/Marlin/src/module/planner.h
@@ -162,7 +162,7 @@ enum BlockFlag : char {
  * A single entry in the planner buffer.
  * Tracks linear movement over multiple axes.
  *
- * The "nominal" values are as-specified by gcode, and
+ * The "nominal" values are as-specified by G-code, and
  * may never actually be reached due to acceleration limits.
  */
 typedef struct block_t {
@@ -411,7 +411,7 @@ class Planner {
 
     /**
      * The current position of the tool in absolute steps
-     * Recalculated if any axis_steps_per_mm are changed by gcode
+     * Recalculated if any axis_steps_per_mm are changed by G-code
      */
     static xyze_long_t position;
 
diff --git a/buildroot/share/scripts/g29_auto.py b/buildroot/share/scripts/g29_auto.py
index ca36346dd9..5cf27b9968 100755
--- a/buildroot/share/scripts/g29_auto.py
+++ b/buildroot/share/scripts/g29_auto.py
@@ -1,13 +1,13 @@
 #!/usr/bin/env python
 
-# This file is for preprocessing gcode and the new G29 Autobedleveling from Marlin
-# It will analyse the first 2 Layer and return the maximum size for this part
-# After this it will replace with g29_keyword = ';MarlinG29Script' with the new G29 LRFB
-# the new file will be created in the same folder.
+# This file is for preprocessing G-code and the new G29 Auto bed leveling from Marlin
+# It will analyze the first 2 layers and return the maximum size for this part
+# Then it will be replaced with g29_keyword = ';MarlinG29Script' with the new G29 LRFB.
+# The new file will be created in the same folder.
 
 from __future__ import print_function
 
-# your gcode-file/folder
+# Your G-code file/folder
 folder = './'
 my_file = 'test.gcode'