diff --git a/src/Symfony/Component/Mailer/CHANGELOG.md b/src/Symfony/Component/Mailer/CHANGELOG.md
index cca04f11aa78e..182a3e7980136 100644
--- a/src/Symfony/Component/Mailer/CHANGELOG.md
+++ b/src/Symfony/Component/Mailer/CHANGELOG.md
@@ -7,6 +7,7 @@ CHANGELOG
  * added `NativeTransportFactory` to configure a transport based on php.ini settings
  * added `local_domain`, `restart_threshold`, `restart_threshold_sleep` and `ping_threshold` options for `smtp`
  * added `command` option for `sendmail`
+ * added `MessageSentEvent`
 
 4.4.0
 -----
diff --git a/src/Symfony/Component/Mailer/Event/MessageSentEvent.php b/src/Symfony/Component/Mailer/Event/MessageSentEvent.php
new file mode 100644
index 0000000000000..eda738b52483d
--- /dev/null
+++ b/src/Symfony/Component/Mailer/Event/MessageSentEvent.php
@@ -0,0 +1,47 @@
+<?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\Mailer\Event;
+
+use Symfony\Component\Mailer\Envelope;
+use Symfony\Component\Mailer\SentMessage;
+use Symfony\Component\Mime\RawMessage;
+use Symfony\Contracts\EventDispatcher\Event;
+
+/**
+ * Allows access to SentMessage after the mail has been sent.
+ */
+final class MessageSentEvent extends Event
+{
+    private $message;
+    private $transport;
+
+    public function __construct(SentMessage $message, string $transport)
+    {
+        $this->message = $message;
+        $this->transport = $transport;
+    }
+
+    public function getMessage(): SentMessage
+    {
+        return $this->message;
+    }
+
+    public function setMessage(SentMessage $message): void
+    {
+        $this->message = $message;
+    }
+
+    public function getTransport(): string
+    {
+        return $this->transport;
+    }
+}
diff --git a/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php b/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
index 12e5d526760ff..3000fd8901fd8 100644
--- a/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
+++ b/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
@@ -12,7 +12,11 @@
 namespace Symfony\Component\Mailer\Tests\Transport;
 
 use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Mailer\Envelope;
+use Symfony\Component\Mailer\Event\MessageEvent;
+use Symfony\Component\Mailer\Event\MessageSentEvent;
 use Symfony\Component\Mailer\Exception\LogicException;
 use Symfony\Component\Mailer\Transport\NullTransport;
 use Symfony\Component\Mime\Address;
@@ -55,4 +59,25 @@ public function testSendingRawMessages()
         $transport = new NullTransport();
         $transport->send(new RawMessage('Some raw email message'));
     }
+
+    public function testEventDispatching()
+    {
+        $message = new RawMessage('');
+        $envelope = new Envelope(new Address('fabien@example.com'), [new Address('helene@example.com')]);
+
+        $eventDispatcher = $this->createMock(EventDispatcherInterface::class);
+
+        // we expect to calls to the dispatcher, first with a MessageEvent, and then with a MessageSentEvent
+        $expectedEvents = [MessageEvent::class, MessageSentEvent::class];
+        $eventDispatcher
+            ->expects($this->exactly(2))
+            ->method('dispatch')
+            ->with($this->callback(function($event) use (&$expectedEvents) {
+                $currentEvent = array_shift($expectedEvents);
+                return $event instanceof $currentEvent;
+            }));
+
+        $transport = new NullTransport($eventDispatcher, $this->createMock(LoggerInterface::class));
+        $transport->send($message, $envelope);
+    }
 }
diff --git a/src/Symfony/Component/Mailer/Transport/AbstractTransport.php b/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
index 0bee2bdb2bbe0..b9e479afc32a4 100644
--- a/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
+++ b/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
@@ -17,6 +17,7 @@
 use Symfony\Component\EventDispatcher\LegacyEventDispatcherProxy;
 use Symfony\Component\Mailer\Envelope;
 use Symfony\Component\Mailer\Event\MessageEvent;
+use Symfony\Component\Mailer\Event\MessageSentEvent;
 use Symfony\Component\Mailer\SentMessage;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\RawMessage;
@@ -67,6 +68,9 @@ public function send(RawMessage $message, Envelope $envelope = null): ?SentMessa
         $message = new SentMessage($message, $envelope);
         $this->doSend($message);
 
+        if (null !== $this->dispatcher) {
+            $this->dispatcher->dispatch(new MessageSentEvent($message, (string) $this));
+        }
         $this->checkThrottling();
 
         return $message;