diff --git a/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransport.php b/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransport.php
index 23afec66bb7df..3cd646f612ab0 100644
--- a/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransport.php
+++ b/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransport.php
@@ -28,11 +28,13 @@ final class MattermostTransport extends AbstractTransport
 {
     private $token;
     private $channel;
+    private $path;
 
-    public function __construct(string $token, string $channel, HttpClientInterface $client = null, EventDispatcherInterface $dispatcher = null)
+    public function __construct(string $token, string $channel, HttpClientInterface $client = null, EventDispatcherInterface $dispatcher = null, string $path = null)
     {
         $this->token = $token;
         $this->channel = $channel;
+        $this->path = $path;
 
         parent::__construct($client, $dispatcher);
     }
@@ -56,14 +58,15 @@ protected function doSend(MessageInterface $message): void
             throw new LogicException(sprintf('The "%s" transport only supports instances of "%s" (instance of "%s" given).', __CLASS__, ChatMessage::class, get_debug_type($message)));
         }
 
-        $endpoint = sprintf('https://%s/api/v4/posts', $this->getEndpoint());
-
         $options = ($opts = $message->getOptions()) ? $opts->toArray() : [];
         $options['message'] = $message->getSubject();
 
         if (!isset($options['channel_id'])) {
             $options['channel_id'] = $message->getRecipientId() ?: $this->channel;
         }
+
+        $endpoint = sprintf('https://%s/api/v4/posts', $this->getEndpoint());
+
         $response = $this->client->request('POST', $endpoint, [
             'auth_bearer' => $this->token,
             'json' => array_filter($options),
@@ -75,4 +78,9 @@ protected function doSend(MessageInterface $message): void
             throw new TransportException(sprintf('Unable to post the Mattermost message: %s (%s).', $result['message'], $result['id']), $response);
         }
     }
+
+    protected function getEndpoint(): ?string
+    {
+        return rtrim($this->host.($this->port ? ':'.$this->port : '').($this->path ?? ''), '/');
+    }
 }
diff --git a/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransportFactory.php b/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransportFactory.php
index ad057c6151c21..16ef2dd2fff54 100644
--- a/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransportFactory.php
+++ b/src/Symfony/Component/Notifier/Bridge/Mattermost/MattermostTransportFactory.php
@@ -32,6 +32,7 @@ public function create(Dsn $dsn): TransportInterface
             throw new UnsupportedSchemeException($dsn, 'mattermost', $this->getSupportedSchemes());
         }
 
+        $path = $dsn->getPath();
         $token = $this->getUser($dsn);
         $channel = $dsn->getOption('channel');
 
@@ -42,7 +43,7 @@ public function create(Dsn $dsn): TransportInterface
         $host = $dsn->getHost();
         $port = $dsn->getPort();
 
-        return (new MattermostTransport($token, $channel, $this->client, $this->dispatcher))->setHost($host)->setPort($port);
+        return (new MattermostTransport($token, $channel, $this->client, $this->dispatcher, $path))->setHost($host)->setPort($port);
     }
 
     protected function getSupportedSchemes(): array
diff --git a/src/Symfony/Component/Notifier/Bridge/Mattermost/README.md b/src/Symfony/Component/Notifier/Bridge/Mattermost/README.md
index bbe64754eef6a..5341a22cc078d 100644
--- a/src/Symfony/Component/Notifier/Bridge/Mattermost/README.md
+++ b/src/Symfony/Component/Notifier/Bridge/Mattermost/README.md
@@ -7,11 +7,13 @@ DSN example
 -----------
 
 ```
-MATTERMOST_DSN=mattermost://ACCESS_TOKEN@default?channel=CHANNEL
+MATTERMOST_DSN=mattermost://ACCESS_TOKEN@HOST/PATH?channel=CHANNEL
 ```
 
 where:
  - `ACCESS_TOKEN` is your Mattermost access token
+ - `HOST` is your Mattermost host
+ - `PATH` is your Mattermost sub-path (optional)
  - `CHANNEL` is your Mattermost channel
 
 Resources
diff --git a/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportFactoryTest.php b/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportFactoryTest.php
index daa774130a1f9..a955e22e8cb57 100644
--- a/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportFactoryTest.php
+++ b/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportFactoryTest.php
@@ -31,6 +31,24 @@ public function testCreateWithDsn()
         $this->assertSame('mattermost://host.test?channel=testChannel', (string) $transport);
     }
 
+    public function testCreateWithDsnHostWithSubfolder()
+    {
+        $factory = $this->createFactory();
+
+        $transport = $factory->create(Dsn::fromString('mattermost://accessToken@example.com/sub?channel=testChannel'));
+
+        $this->assertSame('mattermost://example.com/sub?channel=testChannel', (string) $transport);
+    }
+
+    public function testCreateWithDsnHostWithSubfolderWithTrailingSlash()
+    {
+        $factory = $this->createFactory();
+
+        $transport = $factory->create(Dsn::fromString('mattermost://accessToken@example.com/sub/?channel=testChannel'));
+
+        $this->assertSame('mattermost://example.com/sub?channel=testChannel', (string) $transport);
+    }
+
     public function testCreateWithMissingOptionChannelThrowsIncompleteDsnException()
     {
         $factory = $this->createFactory();
diff --git a/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportTest.php b/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportTest.php
index 7bd203baafb7a..606f610c4db9b 100644
--- a/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportTest.php
+++ b/src/Symfony/Component/Notifier/Bridge/Mattermost/Tests/MattermostTransportTest.php
@@ -16,6 +16,7 @@
 use Symfony\Component\Notifier\Exception\LogicException;
 use Symfony\Component\Notifier\Message\ChatMessage;
 use Symfony\Component\Notifier\Message\MessageInterface;
+use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
 use Symfony\Contracts\HttpClient\HttpClientInterface;
 
 /**