diff --git a/core/modules/config_translation/src/ConfigEntityMapper.php b/core/modules/config_translation/src/ConfigEntityMapper.php
index 2ae3095933..ba25b48a74 100644
--- a/core/modules/config_translation/src/ConfigEntityMapper.php
+++ b/core/modules/config_translation/src/ConfigEntityMapper.php
@@ -13,6 +13,7 @@
 use Drupal\Core\Url;
 use Drupal\locale\LocaleConfigManager;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Routing\Route;
 
 /**
@@ -73,9 +74,11 @@ class ConfigEntityMapper extends ConfigNamesMapper {
    *   The entity manager.
    * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
    *   The language manager.
+   * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
+   *   The event dispatcher.
    */
-  public function __construct($plugin_id, $plugin_definition, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config, LocaleConfigManager $locale_config_manager, ConfigMapperManagerInterface $config_mapper_manager, RouteProviderInterface $route_provider, TranslationInterface $translation_manager, EntityManagerInterface $entity_manager, LanguageManagerInterface $language_manager) {
-    parent::__construct($plugin_id, $plugin_definition, $config_factory, $typed_config, $locale_config_manager, $config_mapper_manager, $route_provider, $translation_manager, $language_manager);
+  public function __construct($plugin_id, $plugin_definition, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config, LocaleConfigManager $locale_config_manager, ConfigMapperManagerInterface $config_mapper_manager, RouteProviderInterface $route_provider, TranslationInterface $translation_manager, EntityManagerInterface $entity_manager, LanguageManagerInterface $language_manager, EventDispatcherInterface $event_dispatcher = NULL) {
+    parent::__construct($plugin_id, $plugin_definition, $config_factory, $typed_config, $locale_config_manager, $config_mapper_manager, $route_provider, $translation_manager, $language_manager, $event_dispatcher);
     $this->setType($plugin_definition['entity_type']);
 
     $this->entityManager = $entity_manager;
@@ -97,7 +100,8 @@ public static function create(ContainerInterface $container, array $configuratio
       $container->get('router.route_provider'),
       $container->get('string_translation'),
       $container->get('entity.manager'),
-      $container->get('language_manager')
+      $container->get('language_manager'),
+      $container->get('event_dispatcher')
     );
   }
 
@@ -105,9 +109,9 @@ public static function create(ContainerInterface $container, array $configuratio
    * {@inheritdoc}
    */
   public function populateFromRouteMatch(RouteMatchInterface $route_match) {
-    parent::populateFromRouteMatch($route_match);
     $entity = $route_match->getParameter($this->entityType);
     $this->setEntity($entity);
+    parent::populateFromRouteMatch($route_match);
   }
 
   /**
diff --git a/core/modules/config_translation/src/ConfigMapperInterface.php b/core/modules/config_translation/src/ConfigMapperInterface.php
index 57c1ccd27d..9bb44b4884 100644
--- a/core/modules/config_translation/src/ConfigMapperInterface.php
+++ b/core/modules/config_translation/src/ConfigMapperInterface.php
@@ -282,12 +282,12 @@ public function hasTranslatable();
   public function hasTranslation(LanguageInterface $language);
 
   /**
-   * Populate the config mapper with request data.
-   *
-   * @todo Replace $request with RouteMatch https://www.drupal.org/node/2295255.
+   * Populate the config mapper with route match data.
    *
    * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
    *   The route match.
+   *
+   * @see \Drupal\config_translation\Event\ConfigTranslationEvents::POPULATE_MAPPER
    */
   public function populateFromRouteMatch(RouteMatchInterface $route_match);
 
diff --git a/core/modules/config_translation/src/ConfigNamesMapper.php b/core/modules/config_translation/src/ConfigNamesMapper.php
index 03716e9725..02afedae7a 100644
--- a/core/modules/config_translation/src/ConfigNamesMapper.php
+++ b/core/modules/config_translation/src/ConfigNamesMapper.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\config_translation;
 
+use Drupal\config_translation\Event\ConfigMapperPopulateEvent;
+use Drupal\config_translation\Event\ConfigTranslationEvents;
 use Drupal\config_translation\Exception\ConfigMapperLanguageException;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Config\TypedConfigManagerInterface;
@@ -15,6 +17,7 @@
 use Drupal\Core\Url;
 use Drupal\locale\LocaleConfigManager;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCollection;
 
@@ -87,6 +90,13 @@ class ConfigNamesMapper extends PluginBase implements ConfigMapperInterface, Con
   protected $languageManager;
 
   /**
+   * The event dispatcher.
+   *
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
+   */
+  protected $eventDispatcher;
+
+  /**
    * Constructs a ConfigNamesMapper.
    *
    * @param $plugin_id
@@ -115,23 +125,26 @@ class ConfigNamesMapper extends PluginBase implements ConfigMapperInterface, Con
    *   The string translation manager.
    * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
    *   The language manager.
+   * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
+   *   (optional) The event dispatcher.
    *
    * @throws \Symfony\Component\Routing\Exception\RouteNotFoundException
    *   Throws an exception if the route specified by the 'base_route_name' in
    *   the plugin definition could not be found by the route provider.
+   *
+   * @todo Make $event_dispatcher required in Drupal 9.
    */
-  public function __construct($plugin_id, $plugin_definition, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config, LocaleConfigManager $locale_config_manager, ConfigMapperManagerInterface $config_mapper_manager, RouteProviderInterface $route_provider, TranslationInterface $string_translation, LanguageManagerInterface $language_manager) {
+  public function __construct($plugin_id, $plugin_definition, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config, LocaleConfigManager $locale_config_manager, ConfigMapperManagerInterface $config_mapper_manager, RouteProviderInterface $route_provider, TranslationInterface $string_translation, LanguageManagerInterface $language_manager, EventDispatcherInterface $event_dispatcher = NULL) {
     $this->pluginId = $plugin_id;
     $this->pluginDefinition = $plugin_definition;
-    $this->routeProvider = $route_provider;
-
     $this->configFactory = $config_factory;
     $this->typedConfigManager = $typed_config;
     $this->localeConfigManager = $locale_config_manager;
     $this->configMapperManager = $config_mapper_manager;
-
+    $this->routeProvider = $route_provider;
     $this->stringTranslation = $string_translation;
     $this->languageManager = $language_manager;
+    $this->eventDispatcher = $event_dispatcher ?: \Drupal::service('event_dispatcher');
   }
 
   /**
@@ -149,7 +162,8 @@ public static function create(ContainerInterface $container, array $configuratio
       $container->get('plugin.manager.config_translation.mapper'),
       $container->get('router.route_provider'),
       $container->get('string_translation'),
-      $container->get('language_manager')
+      $container->get('language_manager'),
+      $container->get('event_dispatcher')
     );
   }
 
@@ -368,6 +382,9 @@ public function getWeight() {
    */
   public function populateFromRouteMatch(RouteMatchInterface $route_match) {
     $this->langcode = $route_match->getParameter('langcode');
+
+    $event = new ConfigMapperPopulateEvent($this, $route_match);
+    $this->eventDispatcher->dispatch(ConfigTranslationEvents::POPULATE_MAPPER, $event);
   }
 
   /**
diff --git a/core/modules/config_translation/src/Event/ConfigMapperPopulateEvent.php b/core/modules/config_translation/src/Event/ConfigMapperPopulateEvent.php
new file mode 100644
index 0000000000..e36c41884b
--- /dev/null
+++ b/core/modules/config_translation/src/Event/ConfigMapperPopulateEvent.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Drupal\config_translation\Event;
+
+use Drupal\config_translation\ConfigMapperInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Provides a class for events related to configuration translation mappers.
+ */
+class ConfigMapperPopulateEvent extends Event {
+
+  /**
+   * The configuration mapper this event is related to.
+   *
+   * @var \Drupal\config_translation\ConfigMapperInterface
+   */
+  protected $mapper;
+
+  /**
+   * The route match this event is related to.
+   *
+   * @var \Drupal\Core\Routing\RouteMatchInterface
+   */
+  protected $routeMatch;
+
+  /**
+   * Constructs a ConfigMapperPopulateEvent object.
+   *
+   * @param \Drupal\config_translation\ConfigMapperInterface $mapper
+   *   The configuration mapper this event is related to.
+   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
+   *   The route match this event is related to.
+   */
+  public function __construct(ConfigMapperInterface $mapper, RouteMatchInterface $route_match) {
+    $this->mapper = $mapper;
+    $this->routeMatch = $route_match;
+  }
+
+  /**
+   * Gets the configuration mapper this event is related to.
+   *
+   * @return \Drupal\config_translation\ConfigMapperInterface
+   *   The configuration mapper this event is related to.
+   */
+  public function getMapper() {
+    return $this->mapper;
+  }
+
+  /**
+   * Gets the route match this event is related to.
+   *
+   * @return \Drupal\Core\Routing\RouteMatchInterface
+   *   The route match this event is related to.
+   */
+  public function getRouteMatch() {
+    return $this->routeMatch;
+  }
+
+}
diff --git a/core/modules/config_translation/src/Event/ConfigTranslationEvents.php b/core/modules/config_translation/src/Event/ConfigTranslationEvents.php
new file mode 100644
index 0000000000..da392fa5c7
--- /dev/null
+++ b/core/modules/config_translation/src/Event/ConfigTranslationEvents.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Drupal\config_translation\Event;
+
+/**
+ * Provides a list of events dispatched by the Configuration Translation module.
+ */
+final class ConfigTranslationEvents {
+
+  /**
+   * The name of the event dispatched when a configuration mapper is populated.
+   *
+   * Allows modules to add related config for translation on a specific
+   * translation form.
+   *
+   * @see \Drupal\config_translation\ConfigMapperInterface::populateFromRouteMatch()
+   */
+  const POPULATE_MAPPER = 'config_translation.populate_mapper';
+
+}
+
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.services.yml b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.services.yml
new file mode 100644
index 0000000000..b23d938d78
--- /dev/null
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.services.yml
@@ -0,0 +1,5 @@
+services:
+  config_translation_test_event_subscriber:
+    class: Drupal\config_translation_test\EventSubscriber\ConfigTranslationTestSubscriber
+    tags:
+      - {name: event_subscriber}
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/src/EventSubscriber/ConfigTranslationTestSubscriber.php b/core/modules/config_translation/tests/modules/config_translation_test/src/EventSubscriber/ConfigTranslationTestSubscriber.php
new file mode 100644
index 0000000000..15fc6ac40a
--- /dev/null
+++ b/core/modules/config_translation/tests/modules/config_translation_test/src/EventSubscriber/ConfigTranslationTestSubscriber.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Drupal\config_translation_test\EventSubscriber;
+
+use Drupal\config_translation\Event\ConfigMapperPopulateEvent;
+use Drupal\config_translation\Event\ConfigTranslationEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Adds configuration names to configuration mapper on POPULATE_MAPPER event.
+ */
+class ConfigTranslationTestSubscriber implements EventSubscriberInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    return [
+      ConfigTranslationEvents::POPULATE_MAPPER => [
+        ['addConfigNames'],
+      ],
+    ];
+  }
+
+  /**
+   * Reacts to the populating of a configuration mapper.
+   *
+   * @param \Drupal\config_translation\Event\ConfigMapperPopulateEvent $event
+   *   The configuration mapper event.
+   */
+  public function addConfigNames(ConfigMapperPopulateEvent $event) {
+    $mapper = $event->getMapper();
+    if ($mapper->getBaseRouteName() === 'system.site_information_settings' && $mapper->getLangcode() === 'en') {
+      $mapper->addConfigName('config_translation_test.content');
+    }
+  }
+
+}
diff --git a/core/modules/config_translation/tests/src/Kernel/ConfigMapperTest.php b/core/modules/config_translation/tests/src/Kernel/ConfigMapperTest.php
new file mode 100644
index 0000000000..773246cba9
--- /dev/null
+++ b/core/modules/config_translation/tests/src/Kernel/ConfigMapperTest.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace Drupal\Tests\config_translation\Kernel;
+
+use Drupal\Core\Routing\RouteMatch;
+use Drupal\KernelTests\KernelTestBase;
+use Symfony\Component\Routing\Route;
+
+/**
+ * Tests config mapper.
+ *
+ * @group config_translation
+ */
+class ConfigMapperTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    'config_translation',
+    'config_translation_test',
+    'language',
+    'locale',
+    'system',
+  ];
+
+  /**
+   * Tests adding config names to mapper.
+   */
+  public function testAddingConfigNames() {
+    // Get a config names mapper.
+    $mappers = \Drupal::service('plugin.manager.config_translation.mapper')->getMappers();
+    $mapper = $mappers['system.site_information_settings'];
+
+    // Test that it doesn't contain a config name from config_translation_test.
+    $config_names = $mapper->getConfigNames();
+    $this->assertNotContains('config_translation_test.content', $config_names);
+
+    // Call populateFromRouteMatch() to dispatch the "config mapper populate"
+    // event.
+    $mapper->populateFromRouteMatch(new RouteMatch('test', new Route('/')));
+
+    // Test that it contains the new config name from config_translation_test.
+    $config_names = $mapper->getConfigNames();
+    $this->assertContains('config_translation_test.content', $config_names);
+  }
+
+}
diff --git a/core/modules/config_translation/tests/src/Unit/ConfigEntityMapperTest.php b/core/modules/config_translation/tests/src/Unit/ConfigEntityMapperTest.php
index db316caf57..5a4f9d9a42 100644
--- a/core/modules/config_translation/tests/src/Unit/ConfigEntityMapperTest.php
+++ b/core/modules/config_translation/tests/src/Unit/ConfigEntityMapperTest.php
@@ -49,6 +49,13 @@ class ConfigEntityMapperTest extends UnitTestCase {
    */
   protected $languageManager;
 
+  /**
+   * The mocked event dispatcher.
+   *
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $eventDispatcher;
+
   protected function setUp() {
     $this->entityManager = $this->getMock('Drupal\Core\Entity\EntityManagerInterface');
 
@@ -79,6 +86,8 @@ protected function setUp() {
 
     $this->languageManager = $this->getMock('Drupal\Core\Language\LanguageManagerInterface');
 
+    $this->eventDispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
+
     $this->configEntityMapper = new ConfigEntityMapper(
       'configurable_language',
       $definition,
@@ -89,7 +98,8 @@ protected function setUp() {
       $this->routeProvider,
       $this->getStringTranslationStub(),
       $this->entityManager,
-      $this->languageManager
+      $this->languageManager,
+      $this->eventDispatcher
     );
   }
 
diff --git a/core/modules/config_translation/tests/src/Unit/ConfigFieldMapperTest.php b/core/modules/config_translation/tests/src/Unit/ConfigFieldMapperTest.php
index 8e6d0b903b..3d17e4641e 100644
--- a/core/modules/config_translation/tests/src/Unit/ConfigFieldMapperTest.php
+++ b/core/modules/config_translation/tests/src/Unit/ConfigFieldMapperTest.php
@@ -36,6 +36,13 @@ class ConfigFieldMapperTest extends UnitTestCase {
   protected $entityManager;
 
   /**
+   * The mocked event dispatcher.
+   *
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $eventDispatcher;
+
+  /**
    * {@inheritdoc}
    */
   protected function setUp() {
@@ -54,6 +61,8 @@ protected function setUp() {
       ->disableOriginalConstructor()
       ->getMock();
 
+    $this->eventDispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
+
     $this->configFieldMapper = new ConfigFieldMapper(
       'node_fields',
       $definition,
@@ -64,7 +73,8 @@ protected function setUp() {
       $this->getMock('Drupal\Core\Routing\RouteProviderInterface'),
       $this->getStringTranslationStub(),
       $this->entityManager,
-      $this->getMock('Drupal\Core\Language\LanguageManagerInterface')
+      $this->getMock('Drupal\Core\Language\LanguageManagerInterface'),
+      $this->eventDispatcher
     );
   }
 
diff --git a/core/modules/config_translation/tests/src/Unit/ConfigNamesMapperTest.php b/core/modules/config_translation/tests/src/Unit/ConfigNamesMapperTest.php
index b099c7fa21..aeb6c4a000 100644
--- a/core/modules/config_translation/tests/src/Unit/ConfigNamesMapperTest.php
+++ b/core/modules/config_translation/tests/src/Unit/ConfigNamesMapperTest.php
@@ -88,6 +88,13 @@ class ConfigNamesMapperTest extends UnitTestCase {
    */
   protected $languageManager;
 
+  /**
+   * The mocked event dispatcher.
+   *
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $eventDispatcher;
+
   protected function setUp() {
     $this->routeProvider = $this->getMock('Drupal\Core\Routing\RouteProviderInterface');
 
@@ -122,6 +129,8 @@ protected function setUp() {
 
     $this->languageManager = $this->getMock('Drupal\Core\Language\LanguageManagerInterface');
 
+    $this->eventDispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
+
     $this->configNamesMapper = new TestConfigNamesMapper(
       'system.site_information_settings',
       $this->pluginDefinition,
@@ -131,7 +140,8 @@ protected function setUp() {
       $this->configMapperManager,
       $this->routeProvider,
       $this->getStringTranslationStub(),
-      $this->languageManager
+      $this->languageManager,
+      $this->eventDispatcher
     );
   }