diff --git a/src/Symfony/Component/Mailer/CHANGELOG.md b/src/Symfony/Component/Mailer/CHANGELOG.md
index d58cf3d832353..53b03a0d70fd5 100644
--- a/src/Symfony/Component/Mailer/CHANGELOG.md
+++ b/src/Symfony/Component/Mailer/CHANGELOG.md
@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Dispatch Postmark's "406 - Inactive recipient" API error code as a `PostmarkDeliveryEvent` instead of throwing an exception
+ * Add DSN param `auto_tls` to disable automatic STARTTLS
 
 7.0
 ---
diff --git a/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php b/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
index c2868ccbd8e99..442583a7af179 100644
--- a/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
+++ b/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
@@ -157,5 +157,28 @@ public static function createProvider(): iterable
             new Dsn('smtps', 'example.com', '', '', 465, ['ping_threshold' => '10']),
             $transport,
         ];
+
+        $transport = new EsmtpTransport('example.com', 25, false, null, $logger);
+        $transport->setAutoTls(false);
+
+        yield [
+            new Dsn('smtp', 'example.com', '', '', 25, ['auto_tls' => false]),
+            $transport,
+        ];
+        yield [
+            new Dsn('smtp', 'example.com', '', '', 0, ['auto_tls' => false]),
+            $transport,
+        ];
+        yield [
+            Dsn::fromString('smtp://:@example.com?auto_tls=false'),
+            $transport,
+        ];
+
+        $transport = new EsmtpTransport('example.com', 465, false, null, $logger);
+        $transport->setAutoTls(false);
+        yield [
+            Dsn::fromString('smtp://:@example.com:465?auto_tls=false'),
+            $transport,
+        ];
     }
 }
diff --git a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php
index 10b673d6a1639..1e23ed4bc5070 100644
--- a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php
+++ b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php
@@ -31,6 +31,7 @@ class EsmtpTransport extends SmtpTransport
     private string $username = '';
     private string $password = '';
     private array $capabilities;
+    private bool $autoTls = true;
 
     public function __construct(string $host = 'localhost', int $port = 0, ?bool $tls = null, ?EventDispatcherInterface $dispatcher = null, ?LoggerInterface $logger = null, ?AbstractStream $stream = null, ?array $authenticators = null)
     {
@@ -99,6 +100,21 @@ public function getPassword(): string
         return $this->password;
     }
 
+    /**
+     * @return $this
+     */
+    public function setAutoTls(bool $autoTls): static
+    {
+        $this->autoTls = $autoTls;
+
+        return $this;
+    }
+
+    public function isAutoTls(): bool
+    {
+        return $this->autoTls;
+    }
+
     public function setAuthenticators(array $authenticators): void
     {
         $this->authenticators = [];
@@ -145,7 +161,7 @@ private function doEhloCommand(): string
         // WARNING: !$stream->isTLS() is right, 100% sure :)
         // if you think that the ! should be removed, read the code again
         // if doing so "fixes" your issue then it probably means your SMTP server behaves incorrectly or is wrongly configured
-        if (!$stream->isTLS() && \defined('OPENSSL_VERSION_NUMBER') && \array_key_exists('STARTTLS', $this->capabilities)) {
+        if ($this->autoTls && !$stream->isTLS() && \defined('OPENSSL_VERSION_NUMBER') && \array_key_exists('STARTTLS', $this->capabilities)) {
             $this->executeCommand("STARTTLS\r\n", [220]);
 
             if (!$stream->startTLS()) {
diff --git a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php
index a15d12245d19b..9df0b957451be 100644
--- a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php
+++ b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php
@@ -23,11 +23,13 @@ final class EsmtpTransportFactory extends AbstractTransportFactory
 {
     public function create(Dsn $dsn): TransportInterface
     {
-        $tls = 'smtps' === $dsn->getScheme() ? true : null;
+        $autoTls = '' === $dsn->getOption('auto_tls') || filter_var($dsn->getOption('auto_tls', true), \FILTER_VALIDATE_BOOL);
+        $tls = 'smtps' === $dsn->getScheme() ? true : ($autoTls ? null : false);
         $port = $dsn->getPort(0);
         $host = $dsn->getHost();
 
         $transport = new EsmtpTransport($host, $port, $tls, $this->dispatcher, $this->logger);
+        $transport->setAutoTls($autoTls);
 
         /** @var SocketStream $stream */
         $stream = $transport->getStream();