diff --git a/plugins/views_plugin_style.inc b/plugins/views_plugin_style.inc
index 4e0946e..059ca13 100644
--- a/plugins/views_plugin_style.inc
+++ b/plugins/views_plugin_style.inc
@@ -305,6 +305,12 @@ class views_plugin_style extends views_plugin {
           if ($group_rendered) {
             $grouping = $group_content;
           }
+          elseif ($this->view->field[$grouping_field]->field_info['type'] == 'datetime') {
+            $field_datetime = $this->get_field_value($index, $grouping_field);
+            $group_column = $this->view->field[$grouping_field]->options['group_column'];
+            $format_type = $this->view->field[$grouping_field]->options['settings']['format_type'];
+            $grouping = format_date(strtotime($field_datetime[0][$group_column]), $format_type);
+          }
           else {
             $grouping = $this->get_field_value($index, $grouping_field);
           }