diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index e68c48563..57c371613 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -1268,6 +1268,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index a70e9cc8d..09a7e3d9d 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -12839,6 +12839,10 @@ void kill(const char* lcd_msg) {
   _delay_ms(250); //Wait to ensure all interrupts routines stopped
   thermalManager.disable_all_heaters(); //turn off heaters again
 
+  #if defined(ACTION_ON_KILL)
+    SERIAL_ECHOLNPGM("//action:" ACTION_ON_KILL);
+  #endif
+  
   #if HAS_POWER_SWITCH
     SET_INPUT(PS_ON_PIN);
   #endif
diff --git a/Marlin/example_configurations/Anet/A6/Configuration_adv.h b/Marlin/example_configurations/Anet/A6/Configuration_adv.h
index 30526adf6..ea27f9331 100644
--- a/Marlin/example_configurations/Anet/A6/Configuration_adv.h
+++ b/Marlin/example_configurations/Anet/A6/Configuration_adv.h
@@ -1268,6 +1268,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/Anet/A8/Configuration_adv.h b/Marlin/example_configurations/Anet/A8/Configuration_adv.h
index cc72206cf..c264b17be 100644
--- a/Marlin/example_configurations/Anet/A8/Configuration_adv.h
+++ b/Marlin/example_configurations/Anet/A8/Configuration_adv.h
@@ -1268,6 +1268,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/Cartesio/Configuration_adv.h b/Marlin/example_configurations/Cartesio/Configuration_adv.h
index 1de847b7f..f71292cbd 100644
--- a/Marlin/example_configurations/Cartesio/Configuration_adv.h
+++ b/Marlin/example_configurations/Cartesio/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/Felix/Configuration_adv.h b/Marlin/example_configurations/Felix/Configuration_adv.h
index 8e5e5fab0..94fcbf30b 100644
--- a/Marlin/example_configurations/Felix/Configuration_adv.h
+++ b/Marlin/example_configurations/Felix/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/FolgerTech-i3-2020/Configuration_adv.h b/Marlin/example_configurations/FolgerTech-i3-2020/Configuration_adv.h
index 5031cfb2d..4b3fb3568 100644
--- a/Marlin/example_configurations/FolgerTech-i3-2020/Configuration_adv.h
+++ b/Marlin/example_configurations/FolgerTech-i3-2020/Configuration_adv.h
@@ -1274,6 +1274,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/Hephestos/Configuration_adv.h b/Marlin/example_configurations/Hephestos/Configuration_adv.h
index bf39fff88..89f30b1fe 100644
--- a/Marlin/example_configurations/Hephestos/Configuration_adv.h
+++ b/Marlin/example_configurations/Hephestos/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/Hephestos_2/Configuration_adv.h b/Marlin/example_configurations/Hephestos_2/Configuration_adv.h
index 4be6605e3..8ee2095aa 100644
--- a/Marlin/example_configurations/Hephestos_2/Configuration_adv.h
+++ b/Marlin/example_configurations/Hephestos_2/Configuration_adv.h
@@ -1244,6 +1244,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/K8200/Configuration_adv.h b/Marlin/example_configurations/K8200/Configuration_adv.h
index d931ab26c..5adbc19d8 100644
--- a/Marlin/example_configurations/K8200/Configuration_adv.h
+++ b/Marlin/example_configurations/K8200/Configuration_adv.h
@@ -1274,6 +1274,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/K8400/Configuration_adv.h b/Marlin/example_configurations/K8400/Configuration_adv.h
index 0f650aa95..04ed926e1 100644
--- a/Marlin/example_configurations/K8400/Configuration_adv.h
+++ b/Marlin/example_configurations/K8400/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/M150/Configuration_adv.h b/Marlin/example_configurations/M150/Configuration_adv.h
index 49bcfcf58..d31f0320a 100644
--- a/Marlin/example_configurations/M150/Configuration_adv.h
+++ b/Marlin/example_configurations/M150/Configuration_adv.h
@@ -1268,6 +1268,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/RigidBot/Configuration_adv.h b/Marlin/example_configurations/RigidBot/Configuration_adv.h
index 84921f225..ac15cd356 100644
--- a/Marlin/example_configurations/RigidBot/Configuration_adv.h
+++ b/Marlin/example_configurations/RigidBot/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/SCARA/Configuration_adv.h b/Marlin/example_configurations/SCARA/Configuration_adv.h
index 59304ae0c..d820ed78b 100644
--- a/Marlin/example_configurations/SCARA/Configuration_adv.h
+++ b/Marlin/example_configurations/SCARA/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/TAZ4/Configuration_adv.h b/Marlin/example_configurations/TAZ4/Configuration_adv.h
index f7184724f..6800a96bc 100644
--- a/Marlin/example_configurations/TAZ4/Configuration_adv.h
+++ b/Marlin/example_configurations/TAZ4/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/TinyBoy2/Configuration_adv.h b/Marlin/example_configurations/TinyBoy2/Configuration_adv.h
index 494d58ca0..5f332f31a 100644
--- a/Marlin/example_configurations/TinyBoy2/Configuration_adv.h
+++ b/Marlin/example_configurations/TinyBoy2/Configuration_adv.h
@@ -1264,6 +1264,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/WITBOX/Configuration_adv.h b/Marlin/example_configurations/WITBOX/Configuration_adv.h
index bf39fff88..89f30b1fe 100644
--- a/Marlin/example_configurations/WITBOX/Configuration_adv.h
+++ b/Marlin/example_configurations/WITBOX/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/delta/FLSUN/auto_calibrate/Configuration_adv.h b/Marlin/example_configurations/delta/FLSUN/auto_calibrate/Configuration_adv.h
index 51019d228..66b681d17 100644
--- a/Marlin/example_configurations/delta/FLSUN/auto_calibrate/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/FLSUN/auto_calibrate/Configuration_adv.h
@@ -1266,6 +1266,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/delta/FLSUN/kossel_mini/Configuration_adv.h b/Marlin/example_configurations/delta/FLSUN/kossel_mini/Configuration_adv.h
index d00185a6a..8de3b0bdf 100644
--- a/Marlin/example_configurations/delta/FLSUN/kossel_mini/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/FLSUN/kossel_mini/Configuration_adv.h
@@ -1265,6 +1265,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/delta/generic/Configuration_adv.h b/Marlin/example_configurations/delta/generic/Configuration_adv.h
index 6fd092e0b..fd2bdf30f 100644
--- a/Marlin/example_configurations/delta/generic/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/generic/Configuration_adv.h
@@ -1263,6 +1263,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h b/Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h
index 6fd092e0b..fd2bdf30f 100644
--- a/Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h
@@ -1263,6 +1263,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h b/Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h
index f2a74f291..f7ae11b99 100644
--- a/Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h
@@ -1268,6 +1268,13 @@
   #define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h b/Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h
index 00a02b39b..ef02e7559 100644
--- a/Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h
@@ -1263,6 +1263,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/gCreate_gMax1.5+/Configuration_adv.h b/Marlin/example_configurations/gCreate_gMax1.5+/Configuration_adv.h
index cf0cc38ef..784624954 100644
--- a/Marlin/example_configurations/gCreate_gMax1.5+/Configuration_adv.h
+++ b/Marlin/example_configurations/gCreate_gMax1.5+/Configuration_adv.h
@@ -1270,6 +1270,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/makibox/Configuration_adv.h b/Marlin/example_configurations/makibox/Configuration_adv.h
index 8a7a61da4..58b2a842d 100644
--- a/Marlin/example_configurations/makibox/Configuration_adv.h
+++ b/Marlin/example_configurations/makibox/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h b/Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h
index 5de0a43bb..de5a967b7 100644
--- a/Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h
+++ b/Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h
@@ -1261,6 +1261,13 @@
   //#define USER_GCODE_5 "G28\nM503"
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================
diff --git a/Marlin/example_configurations/wt150/Configuration_adv.h b/Marlin/example_configurations/wt150/Configuration_adv.h
index 97f73b2e8..bf612de94 100644
--- a/Marlin/example_configurations/wt150/Configuration_adv.h
+++ b/Marlin/example_configurations/wt150/Configuration_adv.h
@@ -1351,6 +1351,13 @@
 
 #endif
 
+/**
+ * Specify an action command to send to the host when the printer is killed.
+ * Will be sent in the form '//action:ACTION_ON_KILL', e.g. '//action:poweroff'.
+ * The host must be configured to handle the action command.
+ */
+//#define ACTION_ON_KILL "poweroff"
+
 //===========================================================================
 //====================== I2C Position Encoder Settings ======================
 //===========================================================================