diff --git a/src/Composer/Config.php b/src/Composer/Config.php
index b6d942c51..beebbc515 100644
--- a/src/Composer/Config.php
+++ b/src/Composer/Config.php
@@ -43,6 +43,7 @@ class Config
         'prepend-autoloader' => true,
         'github-domains' => array('github.com'),
         'github-expose-hostname' => true,
+        'gitlab-domains' => array('gitlab.com'),
         'store-auths' => 'prompt',
         // valid keys without defaults (auth config stuff):
         // github-oauth