diff --git a/core/lib/Drupal/Core/Entity/Query/QueryBase.php b/core/lib/Drupal/Core/Entity/Query/QueryBase.php
index 9ad26e1..d22dbac 100644
--- a/core/lib/Drupal/Core/Entity/Query/QueryBase.php
+++ b/core/lib/Drupal/Core/Entity/Query/QueryBase.php
@@ -239,4 +239,48 @@ public function tableSort(&$headers) {
   function __clone() {
     $this->condition = clone $this->condition;
   }
+
+  /**
+   * Implements Drupal\Core\Database\Query\AlterableInterface::addTag().
+   */
+  public function addTag($tag) {
+    $this->alterTags[$tag] = 1;
+    return $this;
+  }
+
+  /**
+   * Implements Drupal\Core\Database\Query\AlterableInterface::hasTag().
+   */
+  public function hasTag($tag) {
+    return isset($this->alterTags[$tag]);
+  }
+
+  /**
+   * Implements Drupal\Core\Database\Query\AlterableInterface::hasAllTags().
+   */
+  public function hasAllTags() {
+    return !(boolean)array_diff(func_get_args(), array_keys($this->alterTags));
+  }
+
+  /**
+   * Implements Drupal\Core\Database\Query\AlterableInterface::hasAnyTag().
+   */
+  public function hasAnyTag() {
+    return (boolean)array_intersect(func_get_args(), array_keys($this->alterTags));
+  }
+
+  /**
+   * Implements Drupal\Core\Database\Query\AlterableInterface::addMetaData().
+   */
+  public function addMetaData($key, $object) {
+    $this->alterMetaData[$key] = $object;
+    return $this;
+  }
+
+  /**
+   * Implements Drupal\Core\Database\Query\AlterableInterface::getMetaData().
+   */
+  public function getMetaData($key) {
+    return isset($this->alterMetaData[$key]) ? $this->alterMetaData[$key] : NULL;
+  }
 }
diff --git a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
index 477de7d..ec9627e 100644
--- a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
+++ b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
@@ -7,13 +7,15 @@
 
 namespace Drupal\Core\Entity\Query;
 
+use Drupal\Core\Database\Query\AlterableInterface;
+
 /**
  * Interface for entity queries.
  *
  * Never instantiate classes implementing this interface directly. Always use
  * the QueryFactory class.
  */
-interface QueryInterface {
+interface QueryInterface extends AlterableInterface {
 
   /**
    * Gets the entity type for this query.
diff --git a/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Entity/Query.php b/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Entity/Query.php
index 44023ce..4a0b440 100644
--- a/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Entity/Query.php
+++ b/core/modules/field/modules/field_sql_storage/lib/Drupal/field_sql_storage/Entity/Query.php
@@ -100,6 +100,20 @@ public function execute() {
     }
     $sqlQuery->addTag('entity_query');
     $sqlQuery->addTag('entity_query_' . $this->entityType);
+
+    // Add further tags added.
+    if (isset($this->alterTags)) {
+      foreach ($this->alterTags as $tag => $value) {
+        $sqlQuery->addTag($tag);
+      }
+    }
+
+    // Add further metadata added.
+    if (isset($this->alterMetaData)) {
+      foreach ($this->alterMetaData as $key => $value) {
+        $sqlQuery->addMetaData($key, $value);
+      }
+    }
     // This now contains first the table containing entity properties and
     // last the entity base table. They might be the same.
     $sqlQuery->addMetaData('entity_tables', $entity_tables);
diff --git a/core/modules/field/tests/modules/field_test/field_test.module b/core/modules/field/tests/modules/field_test/field_test.module
index a50dc5d..26ef868 100644
--- a/core/modules/field/tests/modules/field_test/field_test.module
+++ b/core/modules/field/tests/modules/field_test/field_test.module
@@ -262,6 +262,17 @@ function field_test_query_efq_table_prefixing_test_alter(&$query) {
   $query->join('test_entity','te2','%alias.ftid = test_entity.ftid');
 }
 
+
+/**
+ * Implements hook_query_TAG_alter() for tag 'efq_metadata_test'.
+ *
+ * @see Drupal\system\Tests\Entity\EntityQueryTest::testMetaData()
+ */
+function field_test_query_efq_metadata_test_alter(&$query) {
+  global $efq_test_metadata;
+  $efq_test_metadata = $query->getMetadata('foo');
+}
+
 /**
  * Implements hook_field_formatter_settings_form_alter().
  */
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityQueryTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityQueryTest.php
index 8c04faa..1882e6f 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityQueryTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityQueryTest.php
@@ -453,4 +453,20 @@ protected function assertBundleOrder($order) {
       $this->assertTrue($ok, format_string("$i is after all entities in bundle2"));
     }
   }
+
+  /**
+   * Test adding a tag and metadata to the Entity query object.
+   *
+   * The tags and metadata should propogate to the SQL query object.
+   */
+  function testMetaData() {
+    $query = entity_query('test_entity');
+    $query
+      ->addTag('efq_metadata_test')
+      ->addMetaData('foo', 'bar')
+      ->execute();
+
+    global $efq_test_metadata;
+    $this->assertEqual($efq_test_metadata, 'bar', 'Tag and metadata propogated to the SQL query object.');
+  }
 }