diff --git a/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php b/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
index cd410f89cc..108921e025 100644
--- a/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
+++ b/src/Symfony/Component/Mailer/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
@@ -81,5 +81,22 @@ class EsmtpTransportFactoryTest extends TransportFactoryTestCase
             new Dsn('smtps', 'example.com', '', '', 465, ['verify_peer' => false]),
             $transport,
         ];
+
+        yield [
+            new Dsn('smtps', 'example.com', '', '', 465, ['verify_peer' => 'false']),
+            $transport,
+        ];
+
+        yield [
+            Dsn::fromString('smtps://:@example.com?verify_peer=0'),
+            $transport,
+        ];
+
+        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+
+        yield [
+            Dsn::fromString('smtps://:@example.com?verify_peer='),
+            $transport,
+        ];
     }
 }
diff --git a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php
index e09963652b..aab222b55b 100644
--- a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php
+++ b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransportFactory.php
@@ -29,7 +29,7 @@ final class EsmtpTransportFactory extends AbstractTransportFactory
 
         $transport = new EsmtpTransport($host, $port, $tls, $this->dispatcher, $this->logger);
 
-        if (!$dsn->getOption('verify_peer', true)) {
+        if ('' !== $dsn->getOption('verify_peer') && !filter_var($dsn->getOption('verify_peer', true), FILTER_VALIDATE_BOOLEAN)) {
             /** @var SocketStream $stream */
             $stream = $transport->getStream();
             $streamOptions = $stream->getStreamOptions();