diff --git a/core/modules/toolbar/toolbar.js b/core/modules/toolbar/toolbar.js
index 2353050..5f66228 100644
--- a/core/modules/toolbar/toolbar.js
+++ b/core/modules/toolbar/toolbar.js
@@ -12,13 +12,31 @@ Drupal.behaviors.toolbar = {
     var $toolbar = $('#toolbar').once('toolbar');
     if ($toolbar.length) {
 
+      // Hide the toolbar menu items underneath an "Administer" link when the
+      // screen is small enough that they will spill over and cause the toolbar
+      // to grow vertically. @todo: Run this whenever the browser window
+      // resizes (rather than on initial page load) if we want to make it fully
+      // responsive.
+      var $toggle = $toolbar.find('a.toggle');
+      var $menu = $toolbar.find('#toolbar-menu');
+      if ($menu.offset().top > 5) {
+        $menu.hide();
+        // Clicking the "Administer" link toggles the menu items, and also
+        // hides the drawer toggle (since that looks out-of-place whenever the
+        // toolbar is expanded vertically).
+        $('<a href="#">' + Drupal.t('Administer') + '</a>').insertBefore($menu).click(function() {
+          $menu.toggle();
+          $toggle.toggle();
+        });
+      }
+
       // Set the initial state of the toolbar.
       Drupal.toolbar.init();
 
       $(window).on('resize.toolbar', Drupal.toolbar.height);
 
       // Toggling toolbar drawer.
-      $toolbar.find('a.toggle').once('toolbar-toggle').click(function(e) {
+      $toggle.once('toolbar-toggle').click(function(e) {
         e.preventDefault();
         Drupal.toolbar.toggle();
         // Allow resize event handlers to recalculate sizes/positions.