diff --git a/src/Symfony/Component/Notifier/Bridge/Discord/DiscordTransport.php b/src/Symfony/Component/Notifier/Bridge/Discord/DiscordTransport.php
index afa98f77d6b3d..3fb2061290f23 100644
--- a/src/Symfony/Component/Notifier/Bridge/Discord/DiscordTransport.php
+++ b/src/Symfony/Component/Notifier/Bridge/Discord/DiscordTransport.php
@@ -29,6 +29,8 @@ final class DiscordTransport extends AbstractTransport
 {
     protected const HOST = 'discord.com';
 
+    private const SUBJECT_LIMIT = 2000;
+
     private $token;
     private $webhookId;
 
@@ -65,7 +67,7 @@ protected function doSend(MessageInterface $message): SentMessage
 
         $content = $message->getSubject();
 
-        if (\strlen($content) > 2000) {
+        if (mb_strlen($content, 'UTF-8') > self::SUBJECT_LIMIT) {
             throw new LogicException('The subject length of a Discord message must not exceed 2000 characters.');
         }
 
diff --git a/src/Symfony/Component/Notifier/Bridge/Discord/Tests/DiscordTransportTest.php b/src/Symfony/Component/Notifier/Bridge/Discord/Tests/DiscordTransportTest.php
index 154a795530fbf..ead3027580662 100644
--- a/src/Symfony/Component/Notifier/Bridge/Discord/Tests/DiscordTransportTest.php
+++ b/src/Symfony/Component/Notifier/Bridge/Discord/Tests/DiscordTransportTest.php
@@ -56,7 +56,7 @@ public function testSendChatMessageWithMoreThan2000CharsThrowsLogicException()
         $this->expectException(LogicException::class);
         $this->expectExceptionMessage('The subject length of a Discord message must not exceed 2000 characters.');
 
-        $transport->send(new ChatMessage(str_repeat('d', 2001)));
+        $transport->send(new ChatMessage(str_repeat('囍', 2001)));
     }
 
     public function testSendWithErrorResponseThrows()