diff --git a/lib/form/selectgroups.php b/lib/form/selectgroups.php
index ed64e716504..99ef7e011af 100644
--- a/lib/form/selectgroups.php
+++ b/lib/form/selectgroups.php
@@ -376,6 +376,9 @@ class MoodleQuickForm_selectgroups extends HTML_QuickForm_element implements tem
         if (is_array($this->_values)) {
             foreach ($this->_values as $key => $val) {
                 foreach ($this->_optGroups as $optGroup) {
+                    if (empty($optGroup['options'])) {
+                        continue;
+                    }
                     for ($i = 0, $optCount = count($optGroup['options']); $i < $optCount; $i++) {
                         if ((string)$val == (string)$optGroup['options'][$i]['attr']['value']) {
                             $value[$key] = $optGroup['options'][$i]['text'];