diff --git a/lib/Twig/FactoryRuntimeLoader.php b/lib/Twig/FactoryRuntimeLoader.php
new file mode 100644
index 000000000..cf7ba9308
--- /dev/null
+++ b/lib/Twig/FactoryRuntimeLoader.php
@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Lazy loads the runtime implementations for a Twig element.
+ *
+ * @author Robin Chalas <robin.chalas@gmail.com>
+ */
+class Twig_FactoryRuntimeLoader implements Twig_RuntimeLoaderInterface
+{
+    private $map;
+
+    /**
+     * @param array $map An array of format [classname => factory callable]
+     */
+    public function __construct(array $map = array())
+    {
+        $this->map = $map;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function load($class)
+    {
+        if (isset($this->map[$class])) {
+            $runtimeFactory = $this->map[$class];
+
+            return $runtimeFactory();
+        }
+    }
+}
diff --git a/test/Twig/Tests/RuntimeFactoryLoaderTest.php b/test/Twig/Tests/RuntimeFactoryLoaderTest.php
new file mode 100644
index 000000000..f418edf78
--- /dev/null
+++ b/test/Twig/Tests/RuntimeFactoryLoaderTest.php
@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+class Twig_Tests_FactoryRuntimeLoaderTest extends PHPUnit_Framework_TestCase
+{
+    public function testLoad()
+    {
+        $loader = new Twig_FactoryRuntimeLoader(array('stdClass' => 'getRuntime'));
+
+        $this->assertInstanceOf('stdClass', $loader->load('stdClass'));
+    }
+
+    public function testLoadReturnsNullForUnmappedRuntime()
+    {
+        $loader = new Twig_FactoryRuntimeLoader();
+
+        $this->assertNull($loader->load('stdClass'));
+    }
+}
+
+function getRuntime()
+{
+    return new stdClass();
+}