diff --git a/src/etc/inc/system.inc b/src/etc/inc/system.inc
index 3b5975c7e..e2ab94b0c 100644
--- a/src/etc/inc/system.inc
+++ b/src/etc/inc/system.inc
@@ -244,7 +244,6 @@ function get_locale_list()
     $locales['de_DE'] = gettext('German');
     $locales['it_IT'] = gettext('Italian');
     $locales['ja_JP'] = gettext('Japanese');
-    $locales['mn_MN'] = gettext('Mongolian');
     $locales['pt_BR'] = gettext('Portuguese (Brazil)');
     $locales['pt_PT'] = gettext('Portuguese (Portugal)');
     $locales['ru_RU'] = gettext('Russian');