diff --git a/DependencyInjection/SwiftmailerTransportFactory.php b/DependencyInjection/SwiftmailerTransportFactory.php
index 0eecdea7..80469762 100644
--- a/DependencyInjection/SwiftmailerTransportFactory.php
+++ b/DependencyInjection/SwiftmailerTransportFactory.php
@@ -39,6 +39,7 @@ public static function createTransport(array $options, RequestContext $requestCo
                 new \Swift_Transport_Esmtp_Auth_CramMd5Authenticator(),
                 new \Swift_Transport_Esmtp_Auth_LoginAuthenticator(),
                 new \Swift_Transport_Esmtp_Auth_PlainAuthenticator(),
+                new \Swift_Transport_Esmtp_Auth_NTLMAuthenticator()
             ));
             $smtpAuthHandler->setUsername($options['username']);
             $smtpAuthHandler->setPassword($options['password']);
@@ -146,7 +147,7 @@ public static function validateConfig($options)
             throw new \InvalidArgumentException(sprintf('The %s encryption is not supported', $options['encryption']));
         }
 
-        if (!in_array($options['auth_mode'], array('plain', 'login', 'cram-md5', null), true)) {
+        if (!in_array($options['auth_mode'], array('plain', 'login', 'cram-md5', 'ntlm', null), true)) {
             throw new \InvalidArgumentException(sprintf('The %s authentication mode is not supported', $options['auth_mode']));
         }
     }
diff --git a/Resources/config/schema/swiftmailer-1.0.xsd b/Resources/config/schema/swiftmailer-1.0.xsd
index 84a24ff9..98fdda8c 100644
--- a/Resources/config/schema/swiftmailer-1.0.xsd
+++ b/Resources/config/schema/swiftmailer-1.0.xsd
@@ -90,6 +90,7 @@
       <xsd:enumeration value="plain" />
       <xsd:enumeration value="login" />
       <xsd:enumeration value="cram-md5" />
+      <xsd:enumeration value="ntlm" />
     </xsd:restriction>
   </xsd:simpleType>