diff --git a/dom/bindings/Errors.msg b/dom/bindings/Errors.msg
index db689e5bc0..a2661597b3 100644
--- a/dom/bindings/Errors.msg
+++ b/dom/bindings/Errors.msg
@@ -111,3 +111,4 @@ MSG_DEF(MSG_PMO_INVALID_MEMBERS, 0, JSEXN_TYPEERR, "PerformanceMeasureOptions ca
 MSG_DEF(MSG_PMO_CONSTRUCTOR_INACCESSIBLE, 0, JSEXN_TYPEERR, "Can't access PerformanceMark constructor, performance is null.")
 MSG_DEF(MSG_PMO_UNEXPECTED_START_TIME, 0, JSEXN_TYPEERR, "Expected startTime >= 0.")
 MSG_DEF(MSG_PMO_INVALID_ATTR_FOR_NON_GLOBAL, 1, JSEXN_TYPEERR, "Cannot get PerformanceTiming attribute values for non-Window global object. Given: {0}.")
+MSG_DEF(MSG_NOT_SUBMIT_BUTTON, 0, JSEXN_TYPEERR, "The submitter is not a submit button.")
diff --git a/dom/html/HTMLFormElement.cpp b/dom/html/HTMLFormElement.cpp
index f44077c54e..a5f2442489 100644
--- a/dom/html/HTMLFormElement.cpp
+++ b/dom/html/HTMLFormElement.cpp
@@ -276,6 +276,41 @@ HTMLFormElement::Submit()
   return rv.StealNSResult();
 }
 
+// https://html.spec.whatwg.org/multipage/forms.html#dom-form-requestsubmit
+void
+HTMLFormElement::RequestSubmit(nsGenericHTMLElement* aSubmitter,
+                               ErrorResult& aRv) {
+  // 1. If submitter is not null, then:
+  if (aSubmitter) {
+    nsCOMPtr<nsIFormControl> fc = do_QueryObject(aSubmitter);
+
+    // 1.1. If submitter is not a submit button, then throw a TypeError.
+    if (!fc || !fc->IsSubmitControl()) {
+      aRv.ThrowTypeError<MSG_NOT_SUBMIT_BUTTON>();
+      return;
+    }
+
+    // 1.2. If submitter's form owner is not this form element, then throw a
+    //      "NotFoundError" DOMException.
+    if (fc->GetFormElement() != this) {
+      aRv.Throw(NS_ERROR_DOM_NOT_FOUND_ERR);
+      return;
+    }
+  }
+
+  // 2. Otherwise, set submitter to this form element.
+  // 3. Submit this form element, from submitter.
+  // We go through the presShell here for the corner case a submit event
+  // is pending while the window is being destroyed.
+  InternalFormEvent event(true, eFormSubmit);
+  event.mOriginator = aSubmitter;
+  nsEventStatus status = nsEventStatus_eIgnore;
+  nsCOMPtr<nsIPresShell> presShell = GetComposedDoc()->GetShell();
+  if (MOZ_LIKELY(presShell)) {
+    presShell->HandleDOMEventWithTarget(this, &event, &status);
+  }
+}
+
 NS_IMETHODIMP
 HTMLFormElement::Reset()
 {
diff --git a/dom/html/HTMLFormElement.h b/dom/html/HTMLFormElement.h
index b0d355d5a7..e752fd5a82 100644
--- a/dom/html/HTMLFormElement.h
+++ b/dom/html/HTMLFormElement.h
@@ -391,6 +391,19 @@ public:
 
   void Submit(ErrorResult& aRv);
 
+  /**
+   * Requests to submit the form. Unlike submit(), this method includes
+   * interactive constraint validation and firing a submit event,
+   * either of which can cancel submission.
+   *
+   * @param aSubmitter The submitter argument can be used to point to a specific
+   *                   submit button.
+   * @param aRv        An ErrorResult.
+   * @see
+   * https://html.spec.whatwg.org/multipage/forms.html#dom-form-requestsubmit
+   */
+  void RequestSubmit(nsGenericHTMLElement* aSubmitter, ErrorResult& aRv);
+
   // XPCOM Reset() is OK
 
   bool CheckValidity()
diff --git a/dom/webidl/HTMLFormElement.webidl b/dom/webidl/HTMLFormElement.webidl
index 064fe9fade..a1407a718e 100644
--- a/dom/webidl/HTMLFormElement.webidl
+++ b/dom/webidl/HTMLFormElement.webidl
@@ -43,6 +43,8 @@ interface HTMLFormElement : HTMLElement {
 
   [Throws]
   void submit();
+  [Pref="dom.forms.requestsubmit.enabled", Throws]
+  void requestSubmit(optional HTMLElement? submitter = null);
   [CEReactions]
   void reset();
   boolean checkValidity();
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index cd7b37dffb..5f7d02ac62 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1203,6 +1203,9 @@ pref("dom.forms.autocomplete.experimental", false);
 // Enables requestAutocomplete DOM API on forms.
 pref("dom.forms.requestAutocomplete", false);
 
+// Enables requestSubmit DOM API on forms.
+pref("dom.forms.requestsubmit.enabled", true);
+
 // Enable Directory API. By default, disabled.
 pref("dom.input.dirpicker", false);