diff --git a/core/lib/Drupal/Component/Plugin/Factory/DefaultFactory.php b/core/lib/Drupal/Component/Plugin/Factory/DefaultFactory.php
index d049814..ebada0a 100644
--- a/core/lib/Drupal/Component/Plugin/Factory/DefaultFactory.php
+++ b/core/lib/Drupal/Component/Plugin/Factory/DefaultFactory.php
@@ -31,6 +31,13 @@ class DefaultFactory implements FactoryInterface {
   protected $discovery;
 
   /**
+   * Stores the interface the plugin should have.
+   *
+   * @var string
+   */
+  protected $interface;
+
+  /**
    * Constructs a Drupal\Component\Plugin\Factory\DefaultFactory object.
    */
   public function __construct(DiscoveryInterface $discovery) {
@@ -38,11 +45,31 @@ public function __construct(DiscoveryInterface $discovery) {
   }
 
   /**
+   * Set the interface used for the plugin.
+   *
+   * @param string
+   *   The interface the plugin should have.
+   */
+  public function setInterface($interface) {
+    $this->interface = $interface;
+  }
+
+  /**
    * Implements Drupal\Component\Plugin\Factory\FactoryInterface::createInstance().
    */
   public function createInstance($plugin_id, array $configuration) {
     $plugin_definition = $this->discovery->getDefinition($plugin_id);
     $plugin_class = static::getPluginClass($plugin_id, $plugin_definition);
+
+    // Validate the interface of the class.
+    if (isset($this->interface)) {
+      $interfaces = class_implements($plugin_class);
+      if (!isset($interfaces[$this->interface])) {
+        throw new PluginException(sprintf('Plugin (%s) instance class "%s" has to implement interface %s', $plugin_id, $plugin_class, $this->interface));
+      }
+    }
+
+
     return new $plugin_class($configuration, $plugin_id, $plugin_definition);
   }
 
diff --git a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Apple.php b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Apple.php
index fd3fb2f..6a59327 100644
--- a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Apple.php
+++ b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Apple.php
@@ -16,5 +16,7 @@
  *   color = "green"
  * )
  */
-class Apple {}
+class Apple implements FruitInterface {
+
+}
 
diff --git a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Banana.php b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Banana.php
index 55f1d12..71f5bb1 100644
--- a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Banana.php
+++ b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/Banana.php
@@ -20,6 +20,6 @@
  *   }
  * )
  */
-class Banana {
+class Banana implements FruitInterface {
 
 }
diff --git a/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/FruitInterface.php b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/FruitInterface.php
new file mode 100644
index 0000000..a55efc7
--- /dev/null
+++ b/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/FruitInterface.php
@@ -0,0 +1,15 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\plugin_test\Plugin\plugin_test\fruit\FruitInterface.
+ */
+
+namespace Drupal\plugin_test\Plugin\plugin_test\fruit;
+
+/**
+ * Defines an interface for fruit plugins.
+ */
+interface FruitInterface {
+
+} 
diff --git a/core/tests/Drupal/Tests/Component/Plugin/Factory/DefaultPluginFactoryTest.php b/core/tests/Drupal/Tests/Component/Plugin/Factory/DefaultPluginFactoryTest.php
new file mode 100644
index 0000000..f3096b9
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/Plugin/Factory/DefaultPluginFactoryTest.php
@@ -0,0 +1,118 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Component\Plugin\Factory\DefaultPluginFactoryTest.
+ */
+
+namespace Drupal\Tests\Component\Plugin\Factory;
+
+use Drupal\Component\Plugin\Factory\DefaultFactory;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Tests the default plugin factory.
+ *
+ * @see \Drupal\Component\Plugin\DefaultFactory
+ */
+class DefaultPluginFactoryTest extends UnitTestCase {
+
+  /**
+   * The mocked plugin discovery.
+   *
+   * @var \Drupal\Component\Plugin\Discovery\DiscoveryInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $discovery;
+
+  /**
+   * The tested default factory.
+   *
+   * @var \Drupal\Component\Plugin\Factory\DefaultFactory
+   */
+  protected $defaultFactory;
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Default plugin factory',
+      'description' => 'Tests the default plugin factory.',
+      'group' => 'Plugin',
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->discovery = $this->getMock('Drupal\Component\Plugin\Discovery\DiscoveryInterface');
+    $this->defaultFactory = new DefaultFactory($this->discovery);
+  }
+
+  /**
+   * Tests the getPluginClass method.
+   *
+   * @see \Drupal\Component\Plugin\DefaultFactory::getPluginClass
+   * @dataProvider providerTestGetPluginClass
+   */
+  public function testGetPluginClass($plugin_id, $plugin_definition) {
+    $this->discovery->expects($this->once())
+      ->method('getDefinition')
+      ->with($plugin_id)
+      ->will($this->returnValue($plugin_definition));
+    $this->defaultFactory->setInterface('Drupal\plugin_test\Plugin\plugin_test\fruit\FruitInterface');
+    $instance = $this->defaultFactory->createInstance($plugin_id, array());
+
+    $this->assertInstanceOf($plugin_definition['class'], $instance);
+    $this->assertInstanceOf('Drupal\plugin_test\Plugin\plugin_test\fruit\FruitInterface', $instance);
+  }
+
+  /**
+   * Provides plugin_id/plugin_definition which are valid.
+   *
+   * @return array
+   *   An array of plugin IDs and plugin definitions.
+   *
+   * @see self::testGetPluginClassWithInvalidInput
+   */
+  public function providerTestGetPluginClass() {
+    return array(
+      array('apple', array('class' => '\Drupal\plugin_test\Plugin\plugin_test\fruit\Apple')),
+      array('banana', array('class' => '\Drupal\plugin_test\Plugin\plugin_test\fruit\Banana')),
+    );
+  }
+
+
+  /**
+   * Tests the getPluginClass method with invalid input.
+   *
+   * @expectedException \Drupal\Component\Plugin\Exception\PluginException
+   * @dataProvider providerTestGetPluginClassWithInvalidInput
+   */
+  public function testGetPluginClassWithInvalidInput($plugin_id, $plugin_definition) {
+    $this->discovery->expects($this->once())
+      ->method('getDefinition')
+      ->with($plugin_id)
+      ->will($this->returnValue($plugin_definition));
+    $this->defaultFactory->setInterface('Drupal\plugin_test\Plugin\plugin_test\fruit\FruitInterface');
+    $this->defaultFactory->createInstance($plugin_id, array());
+  }
+
+  /**
+   * Provides plugin_id/plugin_definitions which are invalid.
+   *
+   * @return array
+   *   An array of plugin IDs and plugin definitions.
+   *
+   * @see self::testGetPluginClassWithInvalidInput
+   */
+  public function providerTestGetPluginClassWithInvalidInput() {
+    return array(
+      // Provide no class definition.
+      array('rasperry', array()),
+      // Provide a non existing class.
+      array('rasperry', array('class' => '\Drupal\plugin_test\Plugin\plugin_test\fruit\Rasperry')),
+      // Provide a plugin without FruitInterface.
+      array('orange', array('class' => '\Drupal\plugin_test\Plugin\plugin_test\fruit\Orange')),
+    );
+  }
+
+}