diff --git a/dom/events/EventNameList.h b/dom/events/EventNameList.h
index 71a39c92c558..2624f3d36b0f 100644
--- a/dom/events/EventNameList.h
+++ b/dom/events/EventNameList.h
@@ -177,6 +177,7 @@ EVENT(durationchange, eDurationChange, EventNameType_HTML, eBasicEventClass)
 EVENT(emptied, eEmptied, EventNameType_HTML, eBasicEventClass)
 EVENT(ended, eEnded, EventNameType_HTML, eBasicEventClass)
 EVENT(finish, eMarqueeFinish, EventNameType_HTMLMarqueeOnly, eBasicEventClass)
+EVENT(formdata, eFormData, EventNameType_HTML, eBasicEventClass)
 EVENT(fullscreenchange, eFullscreenChange, EventNameType_HTML, eBasicEventClass)
 EVENT(fullscreenerror, eFullscreenError, EventNameType_HTML, eBasicEventClass)
 EVENT(input, eEditorInput, EventNameType_HTMLXUL, eEditorInputEventClass)
diff --git a/dom/events/test/test_all_synthetic_events.html b/dom/events/test/test_all_synthetic_events.html
index 1d228b3a878b..a5b4366f7ba8 100644
--- a/dom/events/test/test_all_synthetic_events.html
+++ b/dom/events/test/test_all_synthetic_events.html
@@ -130,6 +130,12 @@ const kEventConstructors = {
                                                          return new FontFaceSetLoadEvent(aName, aProps);
                                                        },
                                              },
+  FormDataEvent:                             { create (aName, aProps) {
+                                                        return new FormDataEvent(aName, {
+                                                            formData: new FormData()
+                                                        });
+                                                      },
+                                             },
   GamepadEvent:                              { create (aName, aProps) {
                                                          return new GamepadEvent(aName, aProps);
                                                        },
diff --git a/dom/tests/mochitest/general/test_interfaces.js b/dom/tests/mochitest/general/test_interfaces.js
index 418a4f22fef6..304353b43e91 100644
--- a/dom/tests/mochitest/general/test_interfaces.js
+++ b/dom/tests/mochitest/general/test_interfaces.js
@@ -384,6 +384,8 @@ var interfaceNamesInGlobalScope = [
   // IMPORTANT: Do not change this list without review from a DOM peer!
   { name: "FormData", insecureContext: true },
   // IMPORTANT: Do not change this list without review from a DOM peer!
+  { name: "FormDataEvent", insecureContext: true },
+  // IMPORTANT: Do not change this list without review from a DOM peer!
   { name: "FontFace", insecureContext: true },
   // IMPORTANT: Do not change this list without review from a DOM peer!
   { name: "FontFaceSet", insecureContext: true },
diff --git a/dom/webidl/EventHandler.webidl b/dom/webidl/EventHandler.webidl
index eda811c83296..a40e2322c998 100644
--- a/dom/webidl/EventHandler.webidl
+++ b/dom/webidl/EventHandler.webidl
@@ -50,6 +50,7 @@ interface mixin GlobalEventHandlers {
            attribute EventHandler ondurationchange;
            attribute EventHandler onemptied;
            attribute EventHandler onended;
+           attribute EventHandler onformdata;
            attribute EventHandler oninput;
            attribute EventHandler oninvalid;
            attribute EventHandler onkeydown;
diff --git a/dom/webidl/FormDataEvent.webidl b/dom/webidl/FormDataEvent.webidl
new file mode 100644
index 000000000000..71a87fcbf598
--- /dev/null
+++ b/dom/webidl/FormDataEvent.webidl
@@ -0,0 +1,20 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#the-formdataevent-interface
+ */
+
+[Exposed=Window,
+ Constructor(DOMString type, optional FormDataEventInit eventInitDict = {})]
+interface FormDataEvent : Event {
+  // C++ can't deal with a method called FormData() in the generated code
+  [BinaryName="GetFormData"]
+  readonly attribute FormData formData;
+};
+
+dictionary FormDataEventInit : EventInit {
+  required FormData formData;
+};
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index 62d38504b991..53ea068b16cd 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -1043,6 +1043,7 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'DeviceProximityEvent.webidl',
     'ErrorEvent.webidl',
     'FontFaceSetLoadEvent.webidl',
+    'FormDataEvent.webidl',
     'FrameCrashedEvent.webidl',
     'GamepadAxisMoveEvent.webidl',
     'GamepadButtonEvent.webidl',
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
index 7c4b221f4a61..34ecec1ef9d5 100644
--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -130,6 +130,7 @@ NS_EVENT_MESSAGE(eFormSelect)
 NS_EVENT_MESSAGE(eFormInvalid)
 NS_EVENT_MESSAGE(eFormCheckboxStateChange)
 NS_EVENT_MESSAGE(eFormRadioStateChange)
+NS_EVENT_MESSAGE(eFormData)
 
 // Need separate focus/blur notifications for non-native widgets
 NS_EVENT_MESSAGE(eFocus)
diff --git a/xpcom/ds/StaticAtoms.py b/xpcom/ds/StaticAtoms.py
index 2334e143f011..f81e792f4cf4 100644
--- a/xpcom/ds/StaticAtoms.py
+++ b/xpcom/ds/StaticAtoms.py
@@ -2015,6 +2015,7 @@ STATIC_ATOMS = [
     Atom("ontimeout", "ontimeout"),
     Atom("ontimeupdate", "ontimeupdate"),
     Atom("onended", "onended"),
+    Atom("onformdata", "onformdata"),
     Atom("onratechange", "onratechange"),
     Atom("ondurationchange", "ondurationchange"),
     Atom("onvolumechange", "onvolumechange"),