diff --git a/src/Symfony/Component/Form/Extension/Core/Type/RepeatedType.php b/src/Symfony/Component/Form/Extension/Core/Type/RepeatedType.php
index ffb7520a582b6..3984a5dc60174 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/RepeatedType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/RepeatedType.php
@@ -31,13 +31,24 @@ public function buildForm(FormBuilderInterface $builder, array $options)
             $options['options']['error_bubbling'] = $options['error_bubbling'];
         }
 
+        // children fields must always be mapped
+        $defaultOptions = ['mapped' => true];
+
         $builder
             ->addViewTransformer(new ValueToDuplicatesTransformer([
                 $options['first_name'],
                 $options['second_name'],
             ]))
-            ->add($options['first_name'], $options['type'], array_merge($options['options'], $options['first_options']))
-            ->add($options['second_name'], $options['type'], array_merge($options['options'], $options['second_options']))
+            ->add(
+                $options['first_name'],
+                $options['type'],
+                array_merge($options['options'], $options['first_options'], $defaultOptions)
+            )
+            ->add(
+                $options['second_name'],
+                $options['type'],
+                array_merge($options['options'], $options['second_options'], $defaultOptions)
+            )
         ;
     }
 
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/Type/RepeatedTypeTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/Type/RepeatedTypeTest.php
index 8b4666d6fa5f0..4c7f3be569563 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/Type/RepeatedTypeTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/Type/RepeatedTypeTest.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Form\Tests\Extension\Core\Type;
 
 use Symfony\Component\Form\Form;
+use Symfony\Component\Form\Tests\Fixtures\NotMappedType;
 
 class RepeatedTypeTest extends BaseTypeTest
 {
@@ -78,6 +79,42 @@ public function testSetRequired()
         $this->assertFalse($form['second']->isRequired());
     }
 
+    public function testMappedOverridesDefault()
+    {
+        $form = $this->factory->create(NotMappedType::class);
+        $this->assertFalse($form->getConfig()->getMapped());
+
+        $form = $this->factory->create(static::TESTED_TYPE, null, [
+            'type' => NotMappedType::class,
+        ]);
+
+        $this->assertTrue($form['first']->getConfig()->getMapped());
+        $this->assertTrue($form['second']->getConfig()->getMapped());
+    }
+
+    /**
+     * @param string $configurationKey
+     * @dataProvider notMappedConfigurationKeys
+     */
+    public function testNotMappedInnerIsOverridden($configurationKey)
+    {
+        $form = $this->factory->create(static::TESTED_TYPE, null, [
+            'type' => TextTypeTest::TESTED_TYPE,
+            $configurationKey => ['mapped' => false],
+        ]);
+
+        $this->assertTrue($form['first']->getConfig()->getMapped());
+        $this->assertTrue($form['second']->getConfig()->getMapped());
+    }
+
+    public function notMappedConfigurationKeys()
+    {
+        return [
+            ['first_options'],
+            ['second_options'],
+        ];
+    }
+
     public function testSetInvalidOptions()
     {
         $this->expectException('Symfony\Component\OptionsResolver\Exception\InvalidOptionsException');
diff --git a/src/Symfony/Component/Form/Tests/Fixtures/NotMappedType.php b/src/Symfony/Component/Form/Tests/Fixtures/NotMappedType.php
new file mode 100644
index 0000000000000..14c340b8917af
--- /dev/null
+++ b/src/Symfony/Component/Form/Tests/Fixtures/NotMappedType.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Form\Tests\Fixtures;
+
+use Symfony\Component\Form\AbstractType;
+use Symfony\Component\OptionsResolver\OptionsResolver;
+
+class NotMappedType extends AbstractType
+{
+    public function configureOptions(OptionsResolver $resolver)
+    {
+        $resolver->setDefault('mapped', false);
+    }
+}