diff --git a/browser/base/content/test/tabs/browser.toml b/browser/base/content/test/tabs/browser.toml
index b810b27ee344c..8008d70f0c8b5 100644
--- a/browser/base/content/test/tabs/browser.toml
+++ b/browser/base/content/test/tabs/browser.toml
@@ -236,7 +236,7 @@ support-files = [
 ]
 
 ["browser_overflowScroll.js"]
-fail-if = ["a11y_checks"] # Bug 1854233 scrollbutton-down/up may not be focusable and/or labeled
+fail-if = ["a11y_checks"] # Bugs 1854233 and 1873049 scrollbutton-down/up are not labeled
 skip-if = [
   "win11_2009", # Bug 1797751
 ]
diff --git a/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js b/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js
index e292f47724a54..0b9c6e3d6bff9 100644
--- a/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js
+++ b/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js
@@ -233,18 +233,27 @@ this.AccessibilityUtils = (function () {
     if (!node || !node.ownerGlobal) {
       return false;
     }
-    const toolbar = node.closest("toolbar");
+    const toolbar =
+      node.closest("toolbar") ||
+      node.flattenedTreeParentNode.closest("toolbar");
     if (!toolbar || toolbar.getAttribute("keyNav") != "true") {
       return false;
     }
     // The Go button in the Url Bar is an example of a purposefully
     // non-focusable image toolbar button that provides an mouse/touch-only
     // control for the search query submission, while a keyboard user could
-    // press `Enter` to do it. We do not want to create an extra tab stop for
-    // such controls and the markup would include `keyNav="false"` to flag it.
+    // press `Enter` to do it. Similarly, two scroll buttons that appear when
+    // toolbar is overflowing, and keyboard-only users would actually scroll
+    // tabs in the toolbar while trying to navigate to these controls. When
+    // toolbarbuttons are redundant for keyboard users, we do not want to
+    // create an extra tab stop for such controls, thus we are expecting the
+    // button markup to include `keyNav="false"` attribute to flag it.
     if (node.getAttribute("keyNav") == "false") {
       const ariaRoles = getAriaRoles(accessible);
-      return ariaRoles.includes("button");
+      return (
+        ariaRoles.includes("button") ||
+        accessible.role == Ci.nsIAccessibleRole.ROLE_PUSHBUTTON
+      );
     }
     return node.ownerGlobal.ToolbarKeyboardNavigator._isButton(node);
   }
diff --git a/toolkit/content/widgets/arrowscrollbox.js b/toolkit/content/widgets/arrowscrollbox.js
index b4e421f6ff676..28de96c8d7c5d 100644
--- a/toolkit/content/widgets/arrowscrollbox.js
+++ b/toolkit/content/widgets/arrowscrollbox.js
@@ -21,7 +21,7 @@
       return `
       <html:link rel="stylesheet" href="chrome://global/skin/toolbarbutton.css"/>
       <html:link rel="stylesheet" href="chrome://global/skin/arrowscrollbox.css"/>
-      <toolbarbutton id="scrollbutton-up" part="scrollbutton-up"/>
+      <toolbarbutton id="scrollbutton-up" part="scrollbutton-up" keyNav="false"/>
       <spacer part="overflow-start-indicator"/>
       <box class="scrollbox-clip" part="scrollbox-clip" flex="1">
         <scrollbox part="scrollbox" flex="1">
@@ -29,7 +29,7 @@
         </scrollbox>
       </box>
       <spacer part="overflow-end-indicator"/>
-      <toolbarbutton id="scrollbutton-down" part="scrollbutton-down"/>
+      <toolbarbutton id="scrollbutton-down" part="scrollbutton-down" keyNav="false"/>
     `;
     }