diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 8260b9ded304..714fbf42f707 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -4486,7 +4486,7 @@ void Element::RegUnRegAccessKey(bool aDoReg) {
   }
 
   // We have an access key, so get the ESM from the pres context.
-  if (nsPresContext* presContext = GetPresContext(eForUncomposedDoc)) {
+  if (nsPresContext* presContext = GetPresContext(eForComposedDoc)) {
     EventStateManager* esm = presContext->EventStateManager();
 
     // Register or unregister as appropriate.
diff --git a/dom/html/nsGenericHTMLElement.cpp b/dom/html/nsGenericHTMLElement.cpp
index 67689bc856a8..6e023d7f167c 100644
--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -438,8 +438,11 @@ nsresult nsGenericHTMLElement::BindToTree(BindContext& aContext,
   nsresult rv = nsGenericHTMLElementBase::BindToTree(aContext, aParent);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (IsInUncomposedDoc()) {
+  if (IsInComposedDoc()) {
     RegUnRegAccessKey(true);
+  }
+
+  if (IsInUncomposedDoc()) {
     if (HasName() && CanHaveName(NodeInfo()->NameAtom())) {
       aContext.OwnerDoc().AddToNameTable(
           this, GetParsedAttr(nsGkAtoms::name)->GetAtomValue());
@@ -477,7 +480,7 @@ nsresult nsGenericHTMLElement::BindToTree(BindContext& aContext,
 }
 
 void nsGenericHTMLElement::UnbindFromTree(bool aNullParent) {
-  if (IsInUncomposedDoc()) {
+  if (IsInComposedDoc()) {
     RegUnRegAccessKey(false);
   }
 
@@ -2407,7 +2410,7 @@ bool nsGenericHTMLElement::IsHTMLFocusable(bool aWithMouse, bool* aIsFocusable,
 
 bool nsGenericHTMLElement::PerformAccesskey(bool aKeyCausesActivation,
                                             bool aIsTrustedEvent) {
-  nsPresContext* presContext = GetPresContext(eForUncomposedDoc);
+  nsPresContext* presContext = GetPresContext(eForComposedDoc);
   if (!presContext) {
     return false;
   }
diff --git a/dom/tests/mochitest/webcomponents/chrome.ini b/dom/tests/mochitest/webcomponents/chrome.ini
index ab0b6d09c215..05cb82bf9343 100644
--- a/dom/tests/mochitest/webcomponents/chrome.ini
+++ b/dom/tests/mochitest/webcomponents/chrome.ini
@@ -14,3 +14,4 @@ support-files =
   test_upgrade_page.html
   upgrade_tests.js
 [test_xul_custom_element.xhtml]
+[test_xul_shadowdom_accesskey.xhtml]
diff --git a/dom/tests/mochitest/webcomponents/test_xul_shadowdom_accesskey.xhtml b/dom/tests/mochitest/webcomponents/test_xul_shadowdom_accesskey.xhtml
new file mode 100644
index 000000000000..79fb16727602
--- /dev/null
+++ b/dom/tests/mochitest/webcomponents/test_xul_shadowdom_accesskey.xhtml
@@ -0,0 +1,60 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<window title="XUL ShadowDOM accesskey"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+<script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+<body xmlns="http://www.w3.org/1999/xhtml">
+<a target="_blank" rel="opener"
+   href="https://bugzilla.mozilla.org/show_bug.cgi?id=1037709"
+   title="XUL ShadowDOM accesskey">
+Mozilla Bug 1037709
+</a>
+<div id="container" style="position: relative"></div>
+</body>
+<!-- Tests code -->
+<script type="application/javascript">
+<![CDATA[
+
+const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+const container = document.getElementById("container");
+
+function pressAccessKey(accessKey){
+  synthesizeKey(accessKey, navigator.platform.includes("Mac") ? { altKey: true, ctrlKey: true }
+                                                              : { altKey: true, shiftKey: true });
+}
+
+function testAccesskeyInShadowTree(mode) {
+  add_task(async () => {
+    const host = document.createXULElement("div");
+    container.appendChild(host);
+
+    const shadowRoot = host.attachShadow({mode})
+    const button = document.createXULElement("button");
+    button.innerText = "Click Me";
+    button.setAttribute("accesskey", "g");
+    shadowRoot.appendChild(button);
+
+    // Trigger frame construction which is constructed lazily on XUL Element.
+    button.getBoundingClientRect();
+
+    let isClickFired = false;
+    button.addEventListener("click", function(e) {
+      isClickFired = true;
+    }, { once: true });
+
+    pressAccessKey("g");
+    ok(isClickFired, `button element with accesskey in the shadow tree of ${mode} mode`);
+
+    host.remove();
+  });
+}
+
+testAccesskeyInShadowTree("open");
+testAccesskeyInShadowTree("closed");
+
+]]>
+</script>
+</window>
diff --git a/testing/web-platform/tests/shadow-dom/accesskey.tentative.html b/testing/web-platform/tests/shadow-dom/accesskey.tentative.html
new file mode 100644
index 000000000000..c517830226c2
--- /dev/null
+++ b/testing/web-platform/tests/shadow-dom/accesskey.tentative.html
@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<html>
+<head>
+<title>Shadow DOM: accesskey</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/shadow-dom.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+</head>
+<body>
+<div id="log"></div>
+<div id="container" style="position: relative"></div>
+<script>
+
+const container = document.getElementById('container');
+
+function pressAccessKey(accessKey){
+  let controlKey = '\uE009'; // left Control key
+  let altKey = '\uE00A'; // left Alt key
+  let optionKey = altKey;  // left Option key
+  let shiftKey = '\uE008'; // left Shift key
+  // There are differences in using accesskey across browsers and OS's.
+  // See: // https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/accesskey
+  let isMacOSX = navigator.userAgent.indexOf("Mac") != -1;
+  let osAccessKey = isMacOSX ? [controlKey, optionKey] : [shiftKey, altKey];
+  let actions = new test_driver.Actions();
+  // Press keys.
+  for (let key of osAccessKey) {
+    actions = actions.keyDown(key);
+  }
+  actions = actions
+            .keyDown(accessKey)
+            .addTick()
+            .keyUp(accessKey);
+  osAccessKey.reverse();
+  for (let key of osAccessKey) {
+    actions = actions.keyUp(key);
+  }
+  return actions.send();
+}
+
+function testAccesskeyInShadowTree(mode) {
+  promise_test(async t => {
+    const host = document.createElement('div');
+    container.appendChild(host);
+    t.add_cleanup(() => host.remove());
+
+    const shadowRoot = host.attachShadow({mode});
+    shadowRoot.innerHTML = '<button id="button" accesskey="g">Click Me with Shift+Alt+g or on Mac with Control+Option+g</button>';
+
+    let el = shadowRoot.getElementById("button");
+    let eventWatcher = new EventWatcher(t, el, ['click']);
+    let waitForClick = eventWatcher.wait_for('click');
+
+    await pressAccessKey("g");
+    await waitForClick;
+  }, `button element with accesskey in the shadow tree of ${mode} mode`);
+}
+
+testAccesskeyInShadowTree("open");
+testAccesskeyInShadowTree("closed");
+
+</script>
+</body>
