diff --git a/core/modules/contextual/contextual.toolbar.js b/core/modules/contextual/contextual.toolbar.js
index e44b60b..c5032e6 100644
--- a/core/modules/contextual/contextual.toolbar.js
+++ b/core/modules/contextual/contextual.toolbar.js
@@ -16,7 +16,9 @@
  */
 Drupal.behaviors.contextualToolbar = {
   attach: function (context) {
+    var that = this;
     $('body').once('contextualToolbar-init', function () {
+      var options = $.extend({}, that.defaults);
       var $contextuals = $(context).find('.contextual-links');
       var $tab = $('.js .toolbar .bar .contextual-toolbar-tab');
       var model = new Drupal.contextualToolbar.models.EditToggleModel({
@@ -25,7 +27,8 @@ Drupal.behaviors.contextualToolbar = {
       });
       var view = new Drupal.contextualToolbar.views.EditToggleView({
         el: $tab,
-        model: model
+        model: model,
+        strings: options.strings
       });
 
       // Update the model based on overlay events.
@@ -54,6 +57,18 @@ Drupal.behaviors.contextualToolbar = {
         model.set('isViewing', false);
       }
     });
+  },
+
+  defaults: {
+    strings: {
+      tabbingReleased: Drupal.t('Tabbing is no longer constrained by the Contextual module'),
+      tabbingConstrained: Drupal.t('Tabbing is constrained to a set of @contextualsCount and the Edit mode toggle'),
+      pressEsc: Drupal.t('Press the esc key to exit.'),
+      contextualsCount: {
+        singular: '@count contextual link',
+        plural: '@count contextual links'
+      }
+    }
   }
 };
 
@@ -83,13 +98,22 @@ Drupal.contextualToolbar.views.EditToggleView = Backbone.View.extend({
 
   events: { 'click': 'onClick' },
 
+  // Tracks whether the tabbing constraint announcement has been read once yet.
+  announcedOnce: false,
+
   /**
    * Implements Backbone Views' initialize().
    */
   initialize: function () {
+
+    this.strings = this.options.strings;
+
     this.model.on('change', this.render, this);
     this.model.on('change:isViewing', this.persist, this);
     this.model.on('change:isViewing', this.manageTabbing, this);
+
+    $(document)
+      .on('keyup', $.proxy(this.onKeypress, this));
   },
 
   /**
@@ -104,12 +128,33 @@ Drupal.contextualToolbar.views.EditToggleView = Backbone.View.extend({
     var isViewing = this.model.get('isViewing');
     this.$el.find('button')
       .toggleClass('active', !isViewing)
-      .prop('aria-pressed', !isViewing);
+      .attr('aria-pressed', !isViewing);
 
     return this;
   },
 
   /**
+   * Limits tabbing to the contextual links and edit mode toolbar tab.
+   *
+   * @param Drupal.contextualToolbar.models.EditToggleModel model
+   *   An EditToggleModel Backbone model.
+   * @param bool isViewing
+   *   The value of the isViewing attribute in the model.
+   */
+  manageTabbing: function (model, isViewing) {
+    var tabbingContext = this.model.get('tabbingContext');
+    // Always release an existing tabbing context.
+    if (tabbingContext) {
+      tabbingContext.release();
+    }
+    // Create a new tabbing context when edit mode is enabled.
+    if (!isViewing) {
+      tabbingContext = Drupal.TabbingManager.constrain($('.contextual-toolbar-tab, .contextual'));
+      this.model.set('tabbingContext', tabbingContext);
+    }
+  },
+
+  /**
    * Model change handler; persists the isViewing value to localStorage.
    *
    * isViewing === true is the default, so only stores in localStorage when
@@ -130,39 +175,54 @@ Drupal.contextualToolbar.views.EditToggleView = Backbone.View.extend({
   },
 
   /**
-   * Limits tabbing to the contextual links and edit mode toolbar tab.
-   *
-   * @param Drupal.contextualToolbar.models.EditToggleModel model
-   *   An EditToggleModel Backbone model.
-   * @param bool isViewing
-   *   The value of the isViewing attribute in the model.
+   * Passes state update messsages to Drupal.announce.
    */
-  manageTabbing: function (model, isViewing) {
-    var contextuals = this.model.get('contextuals');
-    // Always release an existing tabbing context.
-    var tabbingContext = this.model.get('tabbingContext');
-    if (tabbingContext) {
-      tabbingContext.release();
-      if (isViewing) {
-        Drupal.announce(Drupal.t('Tabbing is no longer constrained by the Contextual module.'))
-      }
-    }
-    // Create a new tabbing context when edit mode is enabled.
+  announceTabbingConstraint: function () {
+    var isViewing = this.model.get('isViewing');
+
     if (!isViewing) {
-      tabbingContext = Drupal.TabbingManager.constrain($('.contextual-toolbar-tab, .contextual'));
-      this.model.set('tabbingContext', tabbingContext);
-      Drupal.announce(
-        Drupal.t('Tabbing is constrained to set of @contextualsCount and the Edit mode toggle.', {
-          '@contextualsCount': Drupal.formatPlural(contextuals.length, '@count contextual link', '@count contextual links')
-        })
-      );
+      var contextuals = this.model.get('contextuals');
+      Drupal.announce(Drupal.t(this.strings.tabbingConstrained, {
+        '@contextualsCount': Drupal.formatPlural(contextuals.length, this.strings.contextualsCount.singular, this.strings.contextualsCount.plural)
+      }));
+      Drupal.announce(this.strings.pressEsc);
+    }
+    else {
+      Drupal.announce(this.strings.tabbingReleased)
     }
   },
 
+  /**
+   * Responds to the edit mode toggle toolbar button; Toggles edit mode.
+   *
+   * @param jQuery.Event event
+   */
   onClick: function (event) {
     this.model.set('isViewing', !this.model.get('isViewing'));
+    this.announceTabbingConstraint();
+    this.announcedOnce = true;
     event.preventDefault();
     event.stopPropagation();
+  },
+
+  /**
+   * Responds to esc and tab key press events.
+   *
+   * @param jQuery.Event event
+   */
+  onKeypress: function (event) {
+    // Respond to tab key press; Call render so the state announcement is read.
+    // The first tab key press is tracked so that an annoucement about tabbing
+    // constraints can be raised if edit mode is enabled when this page loads.
+    if (!this.announcedOnce && event.keyCode === 9 && !this.model.get('isViewing')) {
+      this.announceTabbingConstraint();
+      // Set announce to true so that this conditional block won't be run again.
+      this.announcedOnce = true;
+    }
+    // Respond to the ESC key. Exit out of edit mode.
+    if (event.keyCode === 27) {
+      this.model.set('isViewing', true);
+    }
   }
 });