diff --git a/src/Symfony/Component/OptionsResolver/OptionsResolver.php b/src/Symfony/Component/OptionsResolver/OptionsResolver.php
index 20ec7af011..e048f67446 100644
--- a/src/Symfony/Component/OptionsResolver/OptionsResolver.php
+++ b/src/Symfony/Component/OptionsResolver/OptionsResolver.php
@@ -312,6 +312,10 @@ class OptionsResolver implements OptionsResolverInterface
     private function validateOptionTypes(array $options)
     {
         foreach ($this->allowedTypes as $option => $allowedTypes) {
+            if (!array_key_exists($option, $options)) {
+                continue;
+            }
+
             $value = $options[$option];
             $allowedTypes = (array) $allowedTypes;
 
diff --git a/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php b/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php
index d90fd72b50..d6e02b0de1 100644
--- a/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php
+++ b/src/Symfony/Component/OptionsResolver/Tests/OptionsResolverTest.php
@@ -381,6 +381,27 @@ class OptionsResolverTest extends \PHPUnit_Framework_TestCase
         ), $this->resolver->resolve($options));
     }
 
+    public function testResolveSucceedsIfOptionalWithTypeAndWithoutValue()
+    {
+        $this->resolver->setOptional(array(
+            'one',
+            'two',
+        ));
+
+        $this->resolver->setAllowedTypes(array(
+            'one' => 'string',
+            'two' => 'int',
+        ));
+
+        $options = array(
+            'two' => 1,
+        );
+
+        $this->assertEquals(array(
+            'two' => 1,
+        ), $this->resolver->resolve($options));
+    }
+
     /**
      * @expectedException Symfony\Component\OptionsResolver\Exception\InvalidOptionsException
      */