diff --git a/apps/files_external/lib/backend/smb.php b/apps/files_external/lib/backend/smb.php
index 350eca1de34..0613d3112ee 100644
--- a/apps/files_external/lib/backend/smb.php
+++ b/apps/files_external/lib/backend/smb.php
@@ -45,10 +45,22 @@ class SMB extends Backend {
 				(new DefinitionParameter('share', $l->t('Share'))),
 				(new DefinitionParameter('root', $l->t('Remote subfolder')))
 					->setFlag(DefinitionParameter::FLAG_OPTIONAL),
+				(new DefinitionParameter('domain', $l->t('Domain')))
+					->setFlag(DefinitionParameter::FLAG_OPTIONAL),
 			])
 			->addAuthScheme(AuthMechanism::SCHEME_PASSWORD)
 			->setLegacyAuthMechanism($legacyAuth)
 		;
 	}
 
+	/**
+	 * @param StorageConfig $storage
+	 */
+	public function manipulateStorageConfig(StorageConfig &$storage) {
+		$user = $storage->getBackendOption('user');
+		if ($domain = $storage->getBackendOption('domain')) {
+			$storage->setBackendOption('user', $domain.'\\'.$user);
+		}
+	}
+
 }