diff --git a/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php
index 951eb9d4a59b8..f381919d8b1dd 100644
--- a/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php
@@ -350,6 +350,10 @@ public function denormalize($data, string $type, string $format = null, array $c
 
         $this->validateCallbackContext($context);
 
+        if (null === $data && isset($context['value_type']) && $context['value_type'] instanceof Type && $context['value_type']->isNullable()) {
+            return null;
+        }
+
         $allowedAttributes = $this->getAllowedAttributes($type, $context, true);
         $normalizedData = $this->prepareForDenormalization($data);
         $extraAttributes = [];
@@ -519,6 +523,8 @@ private function validateAndDenormalize(array $types, string $currentClass, stri
                     if (\count($collectionKeyType = $type->getCollectionKeyTypes()) > 0) {
                         [$context['key_type']] = $collectionKeyType;
                     }
+
+                    $context['value_type'] = $collectionValueType;
                 } elseif ($type->isCollection() && \count($collectionValueType = $type->getCollectionValueTypes()) > 0 && Type::BUILTIN_TYPE_ARRAY === $collectionValueType[0]->getBuiltinType()) {
                     // get inner type for any nested array
                     [$innerType] = $collectionValueType;
diff --git a/src/Symfony/Component/Serializer/Tests/Normalizer/MapDenormalizationTest.php b/src/Symfony/Component/Serializer/Tests/Normalizer/MapDenormalizationTest.php
new file mode 100644
index 0000000000000..6c32fb925b0ff
--- /dev/null
+++ b/src/Symfony/Component/Serializer/Tests/Normalizer/MapDenormalizationTest.php
@@ -0,0 +1,304 @@
+<?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\Serializer\Tests\Normalizer;
+
+use Doctrine\Common\Annotations\AnnotationReader;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\PropertyInfo\Extractor\PhpDocExtractor;
+use Symfony\Component\Serializer\Exception\InvalidArgumentException;
+use Symfony\Component\Serializer\Exception\NotNormalizableValueException;
+use Symfony\Component\Serializer\Mapping\ClassDiscriminatorFromClassMetadata;
+use Symfony\Component\Serializer\Mapping\ClassDiscriminatorMapping;
+use Symfony\Component\Serializer\Mapping\ClassMetadata;
+use Symfony\Component\Serializer\Mapping\ClassMetadataInterface;
+use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
+use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
+use Symfony\Component\Serializer\Mapping\Loader\AnnotationLoader;
+use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
+use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
+use Symfony\Component\Serializer\Serializer;
+
+class MapDenormalizationTest extends TestCase
+{
+    public function testMapOfStringToNullableObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize([
+            'map' => [
+                'assertDummyMapValue' => [
+                    'value' => 'foo',
+                ],
+                'assertNull' => null,
+            ],
+        ], DummyMapOfStringToNullableObject::class);
+
+        $this->assertInstanceOf(DummyMapOfStringToNullableObject::class, $normalizedData);
+
+        // check nullable map value
+        $this->assertIsArray($normalizedData->map);
+
+        $this->assertArrayHasKey('assertDummyMapValue', $normalizedData->map);
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->map['assertDummyMapValue']);
+
+        $this->assertArrayHasKey('assertNull', $normalizedData->map);
+
+        $this->assertNull($normalizedData->map['assertNull']);
+    }
+
+    public function testMapOfStringToAbstractNullableObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize(
+            [
+                'map' => [
+                    'assertNull' => null,
+                ],
+            ], DummyMapOfStringToNullableAbstractObject::class);
+
+        $this->assertInstanceOf(DummyMapOfStringToNullableAbstractObject::class, $normalizedData);
+
+        $this->assertIsArray($normalizedData->map);
+        $this->assertArrayHasKey('assertNull', $normalizedData->map);
+        $this->assertNull($normalizedData->map['assertNull']);
+    }
+
+    public function testMapOfStringToObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize(
+            [
+                'map' => [
+                    'assertDummyMapValue' => [
+                        'value' => 'foo',
+                    ],
+                    'assertEmptyDummyMapValue' => null,
+                ],
+            ], DummyMapOfStringToObject::class);
+
+        $this->assertInstanceOf(DummyMapOfStringToObject::class, $normalizedData);
+
+        // check nullable map value
+        $this->assertIsArray($normalizedData->map);
+
+        $this->assertArrayHasKey('assertDummyMapValue', $normalizedData->map);
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->map['assertDummyMapValue']);
+        $this->assertEquals('foo', $normalizedData->map['assertDummyMapValue']->value);
+
+        $this->assertArrayHasKey('assertEmptyDummyMapValue', $normalizedData->map);
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->map['assertEmptyDummyMapValue']); // correct since to attribute is not nullable
+        $this->assertNull($normalizedData->map['assertEmptyDummyMapValue']->value);
+    }
+
+    public function testMapOfStringToAbstractObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize(
+            [
+                'map' => [
+                    'assertDummyMapValue' => [
+                        'type' => 'dummy',
+                        'value' => 'foo',
+                    ],
+                ],
+            ], DummyMapOfStringToNotNullableAbstractObject::class);
+
+        $this->assertInstanceOf(DummyMapOfStringToNotNullableAbstractObject::class, $normalizedData);
+
+        // check nullable map value
+        $this->assertIsArray($normalizedData->map);
+
+        $this->assertArrayHasKey('assertDummyMapValue', $normalizedData->map);
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->map['assertDummyMapValue']);
+        $this->assertEquals('foo', $normalizedData->map['assertDummyMapValue']->value);
+    }
+
+    public function testMapOfStringToAbstractObjectMissingTypeAttribute()
+    {
+        $this->expectException(NotNormalizableValueException::class);
+        $this->expectExceptionMessage('Type property "type" not found for the abstract object "Symfony\Component\Serializer\Tests\Normalizer\AbstractDummyValue".');
+
+        $this->getSerializer()->denormalize(
+            [
+                'map' => [
+                    'assertEmptyDummyMapValue' => null,
+                ],
+            ], DummyMapOfStringToNotNullableAbstractObject::class);
+    }
+
+    public function testNullableObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize(
+            [
+                'object' => [
+                    'value' => 'foo',
+                ],
+                'nullObject' => null,
+            ], DummyNullableObjectValue::class);
+
+        $this->assertInstanceOf(DummyNullableObjectValue::class, $normalizedData);
+
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->object);
+        $this->assertEquals('foo', $normalizedData->object->value);
+
+        $this->assertNull($normalizedData->nullObject);
+    }
+
+    public function testNotNullableObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize(
+            [
+                'object' => [
+                    'value' => 'foo',
+                ],
+                'nullObject' => null,
+            ], DummyNotNullableObjectValue::class);
+
+        $this->assertInstanceOf(DummyNotNullableObjectValue::class, $normalizedData);
+
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->object);
+        $this->assertEquals('foo', $normalizedData->object->value);
+
+        $this->assertInstanceOf(DummyValue::class, $normalizedData->nullObject);
+        $this->assertNull($normalizedData->nullObject->value);
+    }
+
+    public function testNullableAbstractObject()
+    {
+        $normalizedData = $this->getSerializer()->denormalize(
+            [
+                'object' => [
+                    'type' => 'another-dummy',
+                    'value' => 'foo',
+                ],
+                'nullObject' => null,
+            ], DummyNullableAbstractObjectValue::class);
+
+        $this->assertInstanceOf(DummyNullableAbstractObjectValue::class, $normalizedData);
+
+        $this->assertInstanceOf(AnotherDummyValue::class, $normalizedData->object);
+        $this->assertEquals('foo', $normalizedData->object->value);
+
+        $this->assertNull($normalizedData->nullObject);
+    }
+
+    private function getSerializer()
+    {
+        $loaderMock = new class() implements ClassMetadataFactoryInterface {
+            public function getMetadataFor($value): ClassMetadataInterface
+            {
+                if (AbstractDummyValue::class === $value) {
+                    return new ClassMetadata(
+                        AbstractDummyValue::class,
+                        new ClassDiscriminatorMapping('type', [
+                            'dummy' => DummyValue::class,
+                            'another-dummy' => AnotherDummyValue::class,
+                        ])
+                    );
+                }
+
+                throw new InvalidArgumentException();
+            }
+
+            public function hasMetadataFor($value): bool
+            {
+                return AbstractDummyValue::class === $value;
+            }
+        };
+
+        $factory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
+        $normalizer = new ObjectNormalizer($factory, null, null, new PhpDocExtractor(), new ClassDiscriminatorFromClassMetadata($loaderMock));
+        $serializer = new Serializer([$normalizer, new ArrayDenormalizer()]);
+        $normalizer->setSerializer($serializer);
+
+        return $serializer;
+    }
+}
+
+abstract class AbstractDummyValue
+{
+    public $value;
+}
+
+class DummyValue extends AbstractDummyValue
+{
+}
+
+class AnotherDummyValue extends AbstractDummyValue
+{
+}
+
+class DummyNotNullableObjectValue
+{
+    /**
+     * @var DummyValue
+     */
+    public $object;
+
+    /**
+     * @var DummyValue
+     */
+    public $nullObject;
+}
+
+class DummyNullableObjectValue
+{
+    /**
+     * @var DummyValue|null
+     */
+    public $object;
+
+    /**
+     * @var DummyValue|null
+     */
+    public $nullObject;
+}
+
+class DummyNullableAbstractObjectValue
+{
+    /**
+     * @var AbstractDummyValue|null
+     */
+    public $object;
+
+    /**
+     * @var AbstractDummyValue|null
+     */
+    public $nullObject;
+}
+
+class DummyMapOfStringToNullableObject
+{
+    /**
+     * @var array<string,DummyValue|null>
+     */
+    public $map;
+}
+
+class DummyMapOfStringToObject
+{
+    /**
+     * @var array<string,DummyValue>
+     */
+    public $map;
+}
+
+class DummyMapOfStringToNullableAbstractObject
+{
+    /**
+     * @var array<string,AbstractDummyValue|null>
+     */
+    public $map;
+}
+
+class DummyMapOfStringToNotNullableAbstractObject
+{
+    /**
+     * @var array<string,AbstractDummyValue>
+     */
+    public $map;
+}