diff --git a/builddefs/common_features.mk b/builddefs/common_features.mk
index 2eb7056b6f6..f5b01de015d 100644
--- a/builddefs/common_features.mk
+++ b/builddefs/common_features.mk
@@ -456,6 +456,10 @@ ifeq ($(strip $(RGB_MATRIX_ENABLE)), yes)
     COMMON_VPATH += $(QUANTUM_DIR)/rgb_matrix/animations
     COMMON_VPATH += $(QUANTUM_DIR)/rgb_matrix/animations/runners
     POST_CONFIG_H += $(QUANTUM_DIR)/rgb_matrix/post_config.h
+
+    # TODO: Remove this
+    SRC += $(QUANTUM_DIR)/process_keycode/process_underglow.c
+
     SRC += $(QUANTUM_DIR)/process_keycode/process_rgb_matrix.c
     SRC += $(QUANTUM_DIR)/color.c
     SRC += $(QUANTUM_DIR)/rgb_matrix/rgb_matrix.c
diff --git a/docs/features/rgblight.md b/docs/features/rgblight.md
index 2afc2eb7d09..4322fe796e7 100644
--- a/docs/features/rgblight.md
+++ b/docs/features/rgblight.md
@@ -59,6 +59,10 @@ Changing the **Value** sets the overall brightness.<br>
 
 ## Keycodes
 
+::: warning
+These keycodes also simultaneously control [RGB Matrix](rgb_matrix), if enabled. This behaviour is in the process of being deprecated, so during this time it is recommended to additionally include the dedicated RGB Matrix keycodes to your keymap, and add `#define RGB_MATRIX_DISABLE_SHARED_KEYCODES` to `config.h`.
+:::
+
 |Key                           |Aliases   |Description                                                          |
 |------------------------------|----------|---------------------------------------------------------------------|
 |`QK_UNDERGLOW_TOGGLE`         |`UG_TOGG` |Toggle RGB lighting on or off                                        |
diff --git a/keyboards/inett_studio/sqx/hotswap/config.h b/keyboards/inett_studio/sqx/hotswap/config.h
index 4172a72379f..22d2e739cbb 100644
--- a/keyboards/inett_studio/sqx/hotswap/config.h
+++ b/keyboards/inett_studio/sqx/hotswap/config.h
@@ -20,3 +20,5 @@
 
 #define IS31FL3731_I2C_ADDRESS_1 IS31FL3731_I2C_ADDRESS_GND
 #define IS31FL3731_I2C_ADDRESS_2 IS31FL3731_I2C_ADDRESS_VCC
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/inett_studio/sqx/universal/config.h b/keyboards/inett_studio/sqx/universal/config.h
index 4172a72379f..22d2e739cbb 100644
--- a/keyboards/inett_studio/sqx/universal/config.h
+++ b/keyboards/inett_studio/sqx/universal/config.h
@@ -20,3 +20,5 @@
 
 #define IS31FL3731_I2C_ADDRESS_1 IS31FL3731_I2C_ADDRESS_GND
 #define IS31FL3731_I2C_ADDRESS_2 IS31FL3731_I2C_ADDRESS_VCC
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/kprepublic/bm60hsrgb_ec/rev2/config.h b/keyboards/kprepublic/bm60hsrgb_ec/rev2/config.h
index b58434efece..ddb8a2525ff 100644
--- a/keyboards/kprepublic/bm60hsrgb_ec/rev2/config.h
+++ b/keyboards/kprepublic/bm60hsrgb_ec/rev2/config.h
@@ -16,3 +16,5 @@
 #pragma once
 
 #define IS31FL3733_I2C_ADDRESS_1 IS31FL3733_I2C_ADDRESS_GND_GND
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/kprepublic/bm68hsrgb/rev2/config.h b/keyboards/kprepublic/bm68hsrgb/rev2/config.h
index f35697b992e..026cbdcdca0 100644
--- a/keyboards/kprepublic/bm68hsrgb/rev2/config.h
+++ b/keyboards/kprepublic/bm68hsrgb/rev2/config.h
@@ -17,3 +17,5 @@
 #pragma once
 
 #define IS31FL3741_I2C_ADDRESS_1 IS31FL3741_I2C_ADDRESS_GND
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/mechlovin/adelais/rgb_led/rev2/config.h b/keyboards/mechlovin/adelais/rgb_led/rev2/config.h
index 82b582bfe12..fea263d7fbe 100644
--- a/keyboards/mechlovin/adelais/rgb_led/rev2/config.h
+++ b/keyboards/mechlovin/adelais/rgb_led/rev2/config.h
@@ -2,3 +2,5 @@
 
 #define IS31FL3731_I2C_ADDRESS_1 IS31FL3731_I2C_ADDRESS_GND
 #define IS31FL3731_I2C_ADDRESS_2 IS31FL3731_I2C_ADDRESS_SDA
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/mechlovin/hannah60rgb/rev2/config.h b/keyboards/mechlovin/hannah60rgb/rev2/config.h
index 82b582bfe12..fea263d7fbe 100644
--- a/keyboards/mechlovin/hannah60rgb/rev2/config.h
+++ b/keyboards/mechlovin/hannah60rgb/rev2/config.h
@@ -2,3 +2,5 @@
 
 #define IS31FL3731_I2C_ADDRESS_1 IS31FL3731_I2C_ADDRESS_GND
 #define IS31FL3731_I2C_ADDRESS_2 IS31FL3731_I2C_ADDRESS_SDA
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/owlab/voice65/hotswap/config.h b/keyboards/owlab/voice65/hotswap/config.h
index be6b66e58a8..97bde08548e 100644
--- a/keyboards/owlab/voice65/hotswap/config.h
+++ b/keyboards/owlab/voice65/hotswap/config.h
@@ -18,3 +18,5 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #pragma once
 
 #define IS31FL3741_I2C_ADDRESS_1 IS31FL3741_I2C_ADDRESS_GND
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/owlab/voice65/soldered/config.h b/keyboards/owlab/voice65/soldered/config.h
index be6b66e58a8..97bde08548e 100644
--- a/keyboards/owlab/voice65/soldered/config.h
+++ b/keyboards/owlab/voice65/soldered/config.h
@@ -18,3 +18,5 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #pragma once
 
 #define IS31FL3741_I2C_ADDRESS_1 IS31FL3741_I2C_ADDRESS_GND
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/qwertykeys/qk100/ansi/config.h b/keyboards/qwertykeys/qk100/ansi/config.h
index b78d15782ba..ceba1c798dd 100644
--- a/keyboards/qwertykeys/qk100/ansi/config.h
+++ b/keyboards/qwertykeys/qk100/ansi/config.h
@@ -30,3 +30,5 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define I2C1_DUTY_CYCLE FAST_DUTY_CYCLE_2
 
 #define IS31FL3741_I2C_ADDRESS_1 IS31FL3741_I2C_ADDRESS_GND
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/work_louder/loop/config.h b/keyboards/work_louder/loop/config.h
index b883b0ff578..5b031c6fc10 100644
--- a/keyboards/work_louder/loop/config.h
+++ b/keyboards/work_louder/loop/config.h
@@ -18,3 +18,5 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #pragma once
 
 #define RGBLIGHT_DI_PIN E6
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/work_louder/micro/config.h b/keyboards/work_louder/micro/config.h
index b9f2d8d87dc..6748a5f5951 100644
--- a/keyboards/work_louder/micro/config.h
+++ b/keyboards/work_louder/micro/config.h
@@ -9,3 +9,5 @@
 #define WORK_LOUDER_LED_PIN_1 B6
 #define WORK_LOUDER_LED_PIN_2 B7
 #define WORK_LOUDER_LED_PIN_3 B5
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/work_louder/nano/config.h b/keyboards/work_louder/nano/config.h
index 2372f371b99..492931c559c 100644
--- a/keyboards/work_louder/nano/config.h
+++ b/keyboards/work_louder/nano/config.h
@@ -18,3 +18,5 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #pragma once
 
 #define RGBLIGHT_DI_PIN        C7
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/work_louder/numpad/config.h b/keyboards/work_louder/numpad/config.h
index cfc27d36124..809c498dbbb 100644
--- a/keyboards/work_louder/numpad/config.h
+++ b/keyboards/work_louder/numpad/config.h
@@ -5,3 +5,5 @@
 
 #define RGBLIGHT_DI_PIN D2
 #define RGBLIGHT_DEFAULT_MODE RGBLIGHT_MODE_STATIC_GRADIENT + 9
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/keyboards/work_louder/work_board/config.h b/keyboards/work_louder/work_board/config.h
index 6688711bbbc..efd4c529cd8 100644
--- a/keyboards/work_louder/work_board/config.h
+++ b/keyboards/work_louder/work_board/config.h
@@ -20,3 +20,5 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define RGBLIGHT_DI_PIN        D2
 
 #define RGBLIGHT_DEFAULT_MODE         RGBLIGHT_MODE_STATIC_GRADIENT + 9
+
+#define RGB_MATRIX_DISABLE_SHARED_KEYCODES
diff --git a/quantum/process_keycode/process_underglow.c b/quantum/process_keycode/process_underglow.c
index 779672ac076..6104cd02c6c 100644
--- a/quantum/process_keycode/process_underglow.c
+++ b/quantum/process_keycode/process_underglow.c
@@ -2,87 +2,200 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "process_underglow.h"
-#include "rgblight.h"
+#if defined(RGBLIGHT_ENABLE)
+#    include "rgblight.h"
+#endif
 #include "action_util.h"
 #include "keycodes.h"
 #include "modifiers.h"
 
+// TODO: Remove this
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+#    include "rgb_matrix.h"
+#endif
+
 bool process_underglow(uint16_t keycode, keyrecord_t *record) {
     if (record->event.pressed) {
         uint8_t shifted = get_mods() & MOD_MASK_SHIFT;
         switch (keycode) {
             case QK_UNDERGLOW_TOGGLE:
+#if defined(RGBLIGHT_ENABLE)
                 rgblight_toggle();
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                rgb_matrix_toggle();
+#endif
                 return false;
             case QK_UNDERGLOW_MODE_NEXT:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_step_reverse();
                 } else {
                     rgblight_step();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_step_reverse();
+                } else {
+                    rgb_matrix_step();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_MODE_PREVIOUS:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_step();
                 } else {
                     rgblight_step_reverse();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_step();
+                } else {
+                    rgb_matrix_step_reverse();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_HUE_UP:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_decrease_hue();
                 } else {
                     rgblight_increase_hue();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_decrease_hue();
+                } else {
+                    rgb_matrix_increase_hue();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_HUE_DOWN:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_increase_hue();
                 } else {
                     rgblight_decrease_hue();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_increase_hue();
+                } else {
+                    rgb_matrix_decrease_hue();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_SATURATION_UP:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_decrease_sat();
                 } else {
                     rgblight_increase_sat();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_decrease_sat();
+                } else {
+                    rgb_matrix_increase_sat();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_SATURATION_DOWN:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_increase_sat();
                 } else {
                     rgblight_decrease_sat();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_increase_sat();
+                } else {
+                    rgb_matrix_decrease_sat();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_VALUE_UP:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_decrease_val();
                 } else {
                     rgblight_increase_val();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_decrease_val();
+                } else {
+                    rgb_matrix_increase_val();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_VALUE_DOWN:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
-                    rgblight_increase_hue();
+                    rgblight_increase_val();
                 } else {
-                    rgblight_decrease_hue();
+                    rgblight_decrease_val();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_increase_val();
+                } else {
+                    rgb_matrix_decrease_val();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_SPEED_UP:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_decrease_speed();
                 } else {
                     rgblight_increase_speed();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_decrease_speed();
+                } else {
+                    rgb_matrix_increase_speed();
+                }
+#endif
                 return false;
             case QK_UNDERGLOW_SPEED_DOWN:
+#if defined(RGBLIGHT_ENABLE)
                 if (shifted) {
                     rgblight_increase_speed();
                 } else {
                     rgblight_decrease_speed();
                 }
+#endif
+
+#if defined(RGB_MATRIX_ENABLE) && !defined(RGB_MATRIX_DISABLE_SHARED_KEYCODES)
+                if (shifted) {
+                    rgb_matrix_increase_speed();
+                } else {
+                    rgb_matrix_decrease_speed();
+                }
+#endif
                 return false;
         }
     }
diff --git a/quantum/quantum.c b/quantum/quantum.c
index 8bfe04e1798..874df1593a2 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -60,7 +60,7 @@
 #    include "process_rgb_matrix.h"
 #endif
 
-#if defined(RGBLIGHT_ENABLE)
+#if defined(RGBLIGHT_ENABLE) || defined(RGB_MATRIX_ENABLE)
 #    include "process_underglow.h"
 #endif
 
@@ -382,7 +382,7 @@ bool process_record_quantum(keyrecord_t *record) {
 #ifdef GRAVE_ESC_ENABLE
             process_grave_esc(keycode, record) &&
 #endif
-#if defined(RGBLIGHT_ENABLE)
+#if defined(RGBLIGHT_ENABLE) || defined(RGB_MATRIX_ENABLE)
             process_underglow(keycode, record) &&
 #endif
 #if defined(RGB_MATRIX_ENABLE)