diff --git a/backup/util/ui/base_moodleform.class.php b/backup/util/ui/base_moodleform.class.php
index 520825890e2..b37aff296c6 100644
--- a/backup/util/ui/base_moodleform.class.php
+++ b/backup/util/ui/base_moodleform.class.php
@@ -402,7 +402,8 @@ abstract class base_moodleform extends moodleform {
 
         // Get list of module types on course.
         $modinfo = get_fast_modinfo($COURSE);
-        $modnames = $modinfo->get_used_module_names(true);
+        $modnames = array_map('strval', $modinfo->get_used_module_names(true));
+        core_collator::asort($modnames);
         $PAGE->requires->yui_module('moodle-backup-backupselectall', 'M.core_backup.backupselectall',
                 array($modnames));
         $PAGE->requires->strings_for_js(array('select', 'all', 'none'), 'moodle');