--- a/testing/marionette/client/marionette_driver/marionette.py
+++ b/testing/marionette/client/marionette_driver/marionette.py
@@ -1142,17 +1142,17 @@ class Marionette(object):
 
         :throws InvalidArgumentException: If there are multiple
             `shutdown_flags` ending with `"Quit"`.
 
         """
 
         # The vast majority of this function was implemented inside
         # the quitApplication command as part of bug 1337743, and can be
-        # removed from here in Firefox 54 at the latest.
+        # removed from here in Firefox 55 at the earliest.
 
         # remove duplicates
         flags = set(shutdown_flags)
 
         # add eAttemptQuit if there are no *Quits
         if not any(flag.endswith("Quit") for flag in flags):
             flags = flags | set(("eAttemptQuit",))
 

--- a/testing/marionette/driver.js
+++ b/testing/marionette/driver.js
@@ -2585,16 +2585,21 @@ GeckoDriver.prototype.acceptConnections 
  *
  * @throws {InvalidArgumentError}
  *     If |flags| contains unknown or incompatible flags, for example
  *     multiple Quit flags.
  */
 GeckoDriver.prototype.quitApplication = function* (cmd, resp) {
   const quits = ["eConsiderQuit", "eAttemptQuit", "eForceQuit"];
 
+  // return error if the quit request is cancelled
+  Services.obs.addObserver(() => {
+    throw new UnknownError("Quit was aborted");
+  }, "quit-application-requested", false);
+
   let flags = [];
   if (typeof cmd.parameters.flags != "undefined") {
     flags = assert.array(cmd.parameters.flags);
   }
 
   // bug 1298921
   assert.firefox()