diff --git a/src/Symfony/Component/Mailer/CHANGELOG.md b/src/Symfony/Component/Mailer/CHANGELOG.md
index 772f50717334f..877872ca8ed7e 100644
--- a/src/Symfony/Component/Mailer/CHANGELOG.md
+++ b/src/Symfony/Component/Mailer/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+6.3
+---
+
+ * Add `MessageEvent::reject()` to allow rejecting an email before sending it
+
 6.2
 ---
 
diff --git a/src/Symfony/Component/Mailer/Event/MessageEvent.php b/src/Symfony/Component/Mailer/Event/MessageEvent.php
index 083b8f8435b56..f00fdd52ca24c 100644
--- a/src/Symfony/Component/Mailer/Event/MessageEvent.php
+++ b/src/Symfony/Component/Mailer/Event/MessageEvent.php
@@ -28,6 +28,7 @@ final class MessageEvent extends Event
     private Envelope $envelope;
     private string $transport;
     private bool $queued;
+    private bool $rejected = false;
 
     /** @var StampInterface[] */
     private array $stamps = [];
@@ -70,10 +71,21 @@ public function isQueued(): bool
         return $this->queued;
     }
 
+    public function isRejected(): bool
+    {
+        return $this->rejected;
+    }
+
+    public function reject(): void
+    {
+        $this->rejected = true;
+        $this->stopPropagation();
+    }
+
     public function addStamp(StampInterface $stamp): void
     {
         if (!$this->queued) {
-            throw new LogicException(sprintf('Cannot call "%s()" on a message that is not meant to be queued', __METHOD__));
+            throw new LogicException(sprintf('Cannot call "%s()" on a message that is not meant to be queued.', __METHOD__));
         }
 
         $this->stamps[] = $stamp;
diff --git a/src/Symfony/Component/Mailer/Mailer.php b/src/Symfony/Component/Mailer/Mailer.php
index c9f8b15aa85c1..cd305a65c4926 100644
--- a/src/Symfony/Component/Mailer/Mailer.php
+++ b/src/Symfony/Component/Mailer/Mailer.php
@@ -56,6 +56,10 @@ public function send(RawMessage $message, Envelope $envelope = null): void
             $event = new MessageEvent($clonedMessage, $clonedEnvelope, (string) $this->transport, true);
             $this->dispatcher->dispatch($event);
             $stamps = $event->getStamps();
+
+            if ($event->isRejected()) {
+                return;
+            }
         }
 
         try {
diff --git a/src/Symfony/Component/Mailer/Tests/MailerTest.php b/src/Symfony/Component/Mailer/Tests/MailerTest.php
index a369216e23cbc..95ab9d9391c7b 100644
--- a/src/Symfony/Component/Mailer/Tests/MailerTest.php
+++ b/src/Symfony/Component/Mailer/Tests/MailerTest.php
@@ -13,14 +13,19 @@
 
 use PHPUnit\Framework\TestCase;
 use Psr\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\Mailer\Envelope as MailerEnvelope;
 use Symfony\Component\Mailer\Event\MessageEvent;
 use Symfony\Component\Mailer\Exception\LogicException;
 use Symfony\Component\Mailer\Mailer;
+use Symfony\Component\Mailer\SentMessage;
+use Symfony\Component\Mailer\Transport\AbstractTransport;
 use Symfony\Component\Mailer\Transport\NullTransport;
 use Symfony\Component\Mailer\Transport\TransportInterface;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Messenger\Stamp\StampInterface;
+use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\Email;
 use Symfony\Component\Mime\RawMessage;
 
@@ -78,4 +83,34 @@ public function dispatch($message, array $stamps = []): Envelope
         self::assertCount(1, $bus->stamps);
         self::assertSame([$stamp], $bus->stamps);
     }
+
+    public function testRejectMessage()
+    {
+        $dispatcher = new EventDispatcher();
+        $dispatcher->addListener(MessageEvent::class, fn (MessageEvent $event) => $event->reject(), 255);
+        $dispatcher->addListener(MessageEvent::class, fn () => throw new \RuntimeException('Should never be called.'));
+
+        $transport = new class($dispatcher, $this) extends AbstractTransport {
+            public function __construct(EventDispatcherInterface $dispatcher, private TestCase $test)
+            {
+                parent::__construct($dispatcher);
+            }
+
+            protected function doSend(SentMessage $message): void
+            {
+                $this->test->fail('This should never be called as message is rejected.');
+            }
+
+            public function __toString(): string
+            {
+                return 'fake://';
+            }
+        };
+        $mailer = new Mailer($transport);
+
+        $message = new RawMessage('');
+        $envelope = new MailerEnvelope(new Address('fabien@example.com'), [new Address('helene@example.com')]);
+        $mailer->send($message, $envelope);
+        $this->assertTrue(true);
+    }
 }
diff --git a/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php b/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
index 42c23fcd735e2..19d574f736079 100644
--- a/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
+++ b/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
@@ -15,9 +15,13 @@
 use Symfony\Bridge\Twig\Mime\BodyRenderer;
 use Symfony\Bridge\Twig\Mime\TemplatedEmail;
 use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Mailer\Envelope;
+use Symfony\Component\Mailer\Event\MessageEvent;
 use Symfony\Component\Mailer\EventListener\MessageListener;
 use Symfony\Component\Mailer\Exception\LogicException;
+use Symfony\Component\Mailer\SentMessage;
+use Symfony\Component\Mailer\Transport\AbstractTransport;
 use Symfony\Component\Mailer\Transport\NullTransport;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\RawMessage;
@@ -78,4 +82,32 @@ public function testRenderedTemplatedEmail()
         $sentMessage = $transport->send((new TemplatedEmail())->to('me@example.com')->from('me@example.com')->htmlTemplate('tpl'));
         $this->assertMatchesRegularExpression('/Some message/', $sentMessage->getMessage()->toString());
     }
+
+    public function testRejectMessage()
+    {
+        $dispatcher = new EventDispatcher();
+        $dispatcher->addListener(MessageEvent::class, fn (MessageEvent $event) => $event->reject(), 255);
+        $dispatcher->addListener(MessageEvent::class, fn () => throw new \RuntimeException('Should never be called.'));
+
+        $transport = new class($dispatcher, $this) extends AbstractTransport {
+            public function __construct(EventDispatcherInterface $dispatcher, private TestCase $test)
+            {
+                parent::__construct($dispatcher);
+            }
+
+            protected function doSend(SentMessage $message): void
+            {
+                $this->test->fail('This should never be called as message is rejected.');
+            }
+
+            public function __toString(): string
+            {
+                return 'fake://';
+            }
+        };
+
+        $message = new RawMessage('');
+        $envelope = new Envelope(new Address('fabien@example.com'), [new Address('helene@example.com')]);
+        $this->assertNull($transport->send($message, $envelope));
+    }
 }
diff --git a/src/Symfony/Component/Mailer/Transport/AbstractTransport.php b/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
index a6710d007da02..6598dccfcc09e 100644
--- a/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
+++ b/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
@@ -73,6 +73,10 @@ public function send(RawMessage $message, Envelope $envelope = null): ?SentMessa
 
             $event = new MessageEvent($message, $envelope, (string) $this);
             $this->dispatcher->dispatch($event);
+            if ($event->isRejected()) {
+                return null;
+            }
+
             $envelope = $event->getEnvelope();
             $message = $event->getMessage();