diff --git a/browser/base/content/test/fullscreen/browser.ini b/browser/base/content/test/fullscreen/browser.ini
index bda0b1ef6931..c64441ae5d66 100644
--- a/browser/base/content/test/fullscreen/browser.ini
+++ b/browser/base/content/test/fullscreen/browser.ini
@@ -17,6 +17,7 @@ skip-if = (os == 'mac') || (os == 'linux') # Bug 1648649
 [browser_fullscreen_from_minimize.js]
 skip-if = (os == 'linux') || (os == 'win') # Bug 1818795 and Bug 1818796
 [browser_fullscreen_newtab.js]
+[browser_fullscreen_newwindow.js]
 [browser_fullscreen_permissions_prompt.js]
 [browser_fullscreen_warning.js]
 support-files = fullscreen.html
diff --git a/browser/base/content/test/fullscreen/browser_fullscreen_newwindow.js b/browser/base/content/test/fullscreen/browser_fullscreen_newwindow.js
new file mode 100644
index 000000000000..dee02e2db0dd
--- /dev/null
+++ b/browser/base/content/test/fullscreen/browser_fullscreen_newwindow.js
@@ -0,0 +1,83 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// This test verifies that when in fullscreen mode, and a new window is opened,
+// fullscreen mode should not exit and the url bar is focused.
+add_task(async function test_fullscreen_new_window() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["full-screen-api.enabled", true],
+      ["full-screen-api.allow-trusted-requests-only", false],
+    ],
+  });
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "https://example.org/browser/browser/base/content/test/fullscreen/fullscreen.html"
+  );
+
+  let fullScreenEntered = BrowserTestUtils.waitForEvent(
+    document,
+    "fullscreenchange",
+    false,
+    () => document.fullscreenElement
+  );
+
+  // Enter fullscreen.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    content.document.getElementById("request").click();
+  });
+
+  await fullScreenEntered;
+
+  // Open a new window via ctrl+n.
+  let newWindowPromise = BrowserTestUtils.waitForNewWindow({
+    url: "about:blank",
+  });
+  EventUtils.synthesizeKey("N", { accelKey: true });
+  let newWindow = await newWindowPromise;
+
+  // Check new window state.
+  is(
+    newWindow.document.activeElement,
+    newWindow.gURLBar.inputField,
+    "url bar is focused after new window opened"
+  );
+  ok(
+    !newWindow.fullScreen,
+    "The new chrome window should not be in fullscreen"
+  );
+  ok(
+    !newWindow.document.documentElement.hasAttribute("inDOMFullscreen"),
+    "The new chrome document should not be in fullscreen"
+  );
+
+  // Wait a bit then check the original window state.
+  await new Promise(resolve => TestUtils.executeSoon(resolve));
+  ok(
+    window.fullScreen,
+    "The original chrome window should be still in fullscreen"
+  );
+  ok(
+    document.documentElement.hasAttribute("inDOMFullscreen"),
+    "The original chrome document should be still in fullscreen"
+  );
+
+  // Close new window and move focus back to original window.
+  await BrowserTestUtils.closeWindow(newWindow);
+  await SimpleTest.promiseFocus(window);
+
+  // Exit fullscreen on original window.
+  let fullScreenExited = BrowserTestUtils.waitForEvent(
+    document,
+    "fullscreenchange",
+    false,
+    () => !document.fullscreenElement
+  );
+  EventUtils.synthesizeKey("KEY_Escape");
+  await fullScreenExited;
+
+  BrowserTestUtils.removeTab(tab);
+});