diff --git a/src/State/Provider/DeserializeProvider.php b/src/State/Provider/DeserializeProvider.php
index be399f4f1bf..06bb84ffbf4 100644
--- a/src/State/Provider/DeserializeProvider.php
+++ b/src/State/Provider/DeserializeProvider.php
@@ -75,19 +75,24 @@ public function provide(Operation $operation, array $uriVariables = [], array $c
             throw new UnsupportedMediaTypeHttpException('Format not supported.');
         }
 
-        $method = $operation->getMethod();
-
-        if (
-            null !== $data
-            && (
-                'POST' === $method
+        if ($operation instanceof HttpOperation && null === ($serializerContext[SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE] ?? null)) {
+            $method = $operation->getMethod();
+            $assignObjectToPopulate = 'POST' === $method
                 || 'PATCH' === $method
-                || ('PUT' === $method && !($operation->getExtraProperties()['standard_put'] ?? true))
-            )
-        ) {
+                || ('PUT' === $method && !($operation->getExtraProperties()['standard_put'] ?? true));
+
+            if ($assignObjectToPopulate) {
+                $serializerContext[SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE] = true;
+                trigger_deprecation('api-platform/core', '5.0', 'To assign an object to populate you should set "%s" in your denormalizationContext, not defining it is deprecated.', SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE);
+            }
+        }
+
+        if (null !== $data && ($serializerContext[SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE] ?? false)) {
             $serializerContext[AbstractNormalizer::OBJECT_TO_POPULATE] = $data;
         }
 
+        unset($serializerContext[SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE]);
+
         try {
             return $this->serializer->deserialize((string) $request->getContent(), $serializerContext['deserializer_type'] ?? $operation->getClass(), $format, $serializerContext);
         } catch (PartialDenormalizationException $e) {
diff --git a/src/State/SerializerContextBuilderInterface.php b/src/State/SerializerContextBuilderInterface.php
index cdbbee16698..78f4cf990b8 100644
--- a/src/State/SerializerContextBuilderInterface.php
+++ b/src/State/SerializerContextBuilderInterface.php
@@ -24,6 +24,9 @@
  */
 interface SerializerContextBuilderInterface
 {
+    // @see ApiPlatform\Symfony\Controller\MainController and ApiPlatform\State\Provider\DeserializerProvider
+    public const ASSIGN_OBJECT_TO_POPULATE = 'api_assign_object_to_populate';
+
     /**
      * Creates a serialization context from a Request.
      *
@@ -51,6 +54,7 @@ interface SerializerContextBuilderInterface
      *   api_included?: bool,
      *   attributes?: string[],
      *   deserializer_type?: string,
+     *   api_assign_object_to_populate?: bool,
      * }
      */
     public function createFromRequest(Request $request, bool $normalization, ?array $extractedAttributes = null): array;
diff --git a/src/State/Tests/Provider/DeserializeProviderTest.php b/src/State/Tests/Provider/DeserializeProviderTest.php
index 46710587ac7..34620875df3 100644
--- a/src/State/Tests/Provider/DeserializeProviderTest.php
+++ b/src/State/Tests/Provider/DeserializeProviderTest.php
@@ -14,10 +14,15 @@
 namespace ApiPlatform\State\Tests\Provider;
 
 use ApiPlatform\Metadata\Get;
+use ApiPlatform\Metadata\HttpOperation;
+use ApiPlatform\Metadata\Patch;
 use ApiPlatform\Metadata\Post;
+use ApiPlatform\Metadata\Put;
 use ApiPlatform\State\Provider\DeserializeProvider;
 use ApiPlatform\State\ProviderInterface;
 use ApiPlatform\State\SerializerContextBuilderInterface;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\IgnoreDeprecations;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException;
@@ -26,8 +31,10 @@
 
 class DeserializeProviderTest extends TestCase
 {
+    #[IgnoreDeprecations]
     public function testDeserialize(): void
     {
+        $this->expectUserDeprecationMessage('Since api-platform/core 5.0: To assign an object to populate you should set "api_assign_object_to_populate" in your denormalizationContext, not defining it is deprecated.');
         $objectToPopulate = new \stdClass();
         $serializerContext = [];
         $operation = new Post(deserialize: true, class: 'Test');
@@ -128,4 +135,101 @@ public function testRequestWithEmptyContentType(): void
         $this->expectException(UnsupportedMediaTypeHttpException::class);
         $provider->provide($operation, [], $context);
     }
+
+    #[DataProvider('provideMethodsTriggeringDeprecation')]
+    #[IgnoreDeprecations]
+    public function testDeserializeTriggersDeprecationWhenContextNotSet(HttpOperation $operation): void
+    {
+        $this->expectUserDeprecationMessage('Since api-platform/core 5.0: To assign an object to populate you should set "api_assign_object_to_populate" in your denormalizationContext, not defining it is deprecated.');
+
+        $objectToPopulate = new \stdClass();
+        $serializerContext = [];
+        $decorated = $this->createStub(ProviderInterface::class);
+        $decorated->method('provide')->willReturn($objectToPopulate);
+
+        $serializerContextBuilder = $this->createMock(SerializerContextBuilderInterface::class);
+        $serializerContextBuilder->method('createFromRequest')->willReturn($serializerContext);
+
+        $serializer = $this->createMock(SerializerInterface::class);
+        $serializer->expects($this->once())->method('deserialize')->with(
+            'test',
+            'Test',
+            'format',
+            ['uri_variables' => ['id' => 1], 'object_to_populate' => $objectToPopulate] + $serializerContext
+        )->willReturn(new \stdClass());
+
+        $provider = new DeserializeProvider($decorated, $serializer, $serializerContextBuilder);
+        $request = new Request(content: 'test');
+        $request->headers->set('CONTENT_TYPE', 'ok');
+        $request->attributes->set('input_format', 'format');
+        $provider->provide($operation, ['id' => 1], ['request' => $request]);
+    }
+
+    public static function provideMethodsTriggeringDeprecation(): iterable
+    {
+        yield 'POST method' => [new Post(deserialize: true, class: 'Test')];
+        yield 'PATCH method' => [new Patch(deserialize: true, class: 'Test')];
+        yield 'PUT method (non-standard)' => [new Put(deserialize: true, class: 'Test', extraProperties: ['standard_put' => false])];
+    }
+
+    public function testDeserializeSetsObjectToPopulateWhenContextIsTrue(): void
+    {
+        $objectToPopulate = new \stdClass();
+        $serializerContext = [SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE => true];
+        $operation = new Post(deserialize: true, class: 'Test');
+        $decorated = $this->createStub(ProviderInterface::class);
+        $decorated->method('provide')->willReturn($objectToPopulate);
+
+        $serializerContextBuilder = $this->createMock(SerializerContextBuilderInterface::class);
+        $serializerContextBuilder->method('createFromRequest')->willReturn($serializerContext);
+
+        $serializer = $this->createMock(SerializerInterface::class);
+        $serializer->expects($this->once())->method('deserialize')->with(
+            'test',
+            'Test',
+            'format',
+            $this->callback(function (array $context) use ($objectToPopulate) {
+                $this->assertArrayHasKey(AbstractNormalizer::OBJECT_TO_POPULATE, $context);
+                $this->assertSame($objectToPopulate, $context[AbstractNormalizer::OBJECT_TO_POPULATE]);
+
+                return true;
+            })
+        )->willReturn(new \stdClass());
+
+        $provider = new DeserializeProvider($decorated, $serializer, $serializerContextBuilder);
+        $request = new Request(content: 'test');
+        $request->headers->set('CONTENT_TYPE', 'ok');
+        $request->attributes->set('input_format', 'format');
+        $provider->provide($operation, ['id' => 1], ['request' => $request]);
+    }
+
+    public function testDeserializeDoesNotSetObjectToPopulateWhenContextIsFalse(): void
+    {
+        $objectToPopulate = new \stdClass();
+        $serializerContext = [SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE => false];
+        $operation = new Post(deserialize: true, class: 'Test');
+        $decorated = $this->createStub(ProviderInterface::class);
+        $decorated->method('provide')->willReturn($objectToPopulate);
+
+        $serializerContextBuilder = $this->createMock(SerializerContextBuilderInterface::class);
+        $serializerContextBuilder->method('createFromRequest')->willReturn($serializerContext);
+
+        $serializer = $this->createMock(SerializerInterface::class);
+        $serializer->expects($this->once())->method('deserialize')->with(
+            'test',
+            'Test',
+            'format',
+            $this->callback(function (array $context) {
+                $this->assertArrayNotHasKey(AbstractNormalizer::OBJECT_TO_POPULATE, $context);
+
+                return true;
+            })
+        )->willReturn(new \stdClass());
+
+        $provider = new DeserializeProvider($decorated, $serializer, $serializerContextBuilder);
+        $request = new Request(content: 'test');
+        $request->headers->set('CONTENT_TYPE', 'ok');
+        $request->attributes->set('input_format', 'format');
+        $provider->provide($operation, ['id' => 1], ['request' => $request]);
+    }
 }
diff --git a/src/Symfony/Controller/MainController.php b/src/Symfony/Controller/MainController.php
index 7e9cc8cdfe9..8c691bf654d 100644
--- a/src/Symfony/Controller/MainController.php
+++ b/src/Symfony/Controller/MainController.php
@@ -21,6 +21,7 @@
 use ApiPlatform\Metadata\UriVariablesConverterInterface;
 use ApiPlatform\State\ProcessorInterface;
 use ApiPlatform\State\ProviderInterface;
+use ApiPlatform\State\SerializerContextBuilderInterface;
 use ApiPlatform\State\UriVariablesResolverTrait;
 use ApiPlatform\State\Util\OperationRequestInitiatorTrait;
 use Psr\Log\LoggerInterface;
@@ -48,8 +49,8 @@ public function __invoke(Request $request): Response
     {
         $operation = $this->initializeOperation($request);
 
-        if (!$operation) {
-            throw new RuntimeException('Not an API operation.');
+        if (!$operation || !$operation instanceof HttpOperation) {
+            throw new RuntimeException('Not an HTTP API operation.');
         }
 
         $uriVariables = [];
@@ -72,14 +73,24 @@ public function __invoke(Request $request): Response
             $operation = $operation->withValidate(!$request->isMethodSafe() && !$request->isMethod('DELETE'));
         }
 
-        if (null === $operation->canRead() && $operation instanceof HttpOperation) {
+        if (null === $operation->canRead()) {
             $operation = $operation->withRead($operation->getUriVariables() || $request->isMethodSafe());
         }
 
-        if (null === $operation->canDeserialize() && $operation instanceof HttpOperation) {
+        if (null === $operation->canDeserialize()) {
             $operation = $operation->withDeserialize(\in_array($operation->getMethod(), ['POST', 'PUT', 'PATCH'], true));
         }
 
+        $denormalizationContext = $operation->getDenormalizationContext() ?? [];
+        if ($operation->canDeserialize() && !isset($denormalizationContext[SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE])) {
+            $method = $operation->getMethod();
+            $assignObjectToPopulate = 'POST' === $method
+                || 'PATCH' === $method
+                || ('PUT' === $method && !($operation->getExtraProperties()['standard_put'] ?? true));
+
+            $operation = $operation->withDenormalizationContext($denormalizationContext + [SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE => $assignObjectToPopulate]);
+        }
+
         $body = $this->provider->provide($operation, $uriVariables, $context);
 
         // The provider can change the Operation, extract it again from the Request attributes
diff --git a/src/Symfony/EventListener/DeserializeListener.php b/src/Symfony/EventListener/DeserializeListener.php
index 433f86149dc..403ebc647fe 100644
--- a/src/Symfony/EventListener/DeserializeListener.php
+++ b/src/Symfony/EventListener/DeserializeListener.php
@@ -16,6 +16,7 @@
 use ApiPlatform\Metadata\HttpOperation;
 use ApiPlatform\Metadata\Resource\Factory\ResourceMetadataCollectionFactoryInterface;
 use ApiPlatform\State\ProviderInterface;
+use ApiPlatform\State\SerializerContextBuilderInterface;
 use ApiPlatform\State\Util\OperationRequestInitiatorTrait;
 use ApiPlatform\State\Util\RequestAttributesExtractor;
 use Symfony\Component\HttpKernel\Event\RequestEvent;
@@ -65,6 +66,16 @@ public function onKernelRequest(RequestEvent $event): void
             $operation = $operation->withDeserialize(\in_array($method, ['POST', 'PUT', 'PATCH'], true));
         }
 
+        $denormalizationContext = $operation->getDenormalizationContext() ?? [];
+        if ($operation->canDeserialize() && !isset($denormalizationContext[SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE])) {
+            $method = $operation->getMethod();
+            $assignObjectToPopulate = 'POST' === $method
+                || 'PATCH' === $method
+                || ('PUT' === $method && !($operation->getExtraProperties()['standard_put'] ?? true));
+
+            $operation = $operation->withDenormalizationContext($denormalizationContext + [SerializerContextBuilderInterface::ASSIGN_OBJECT_TO_POPULATE => $assignObjectToPopulate]);
+        }
+
         if (!$operation->canDeserialize()) {
             return;
         }