diff --git a/grade/grading/form/guide/edit_form.php b/grade/grading/form/guide/edit_form.php
index 937f7344b5e..5437beeff27 100644
--- a/grade/grading/form/guide/edit_form.php
+++ b/grade/grading/form/guide/edit_form.php
@@ -51,9 +51,11 @@ class gradingform_guide_editguide extends moodleform {
         $form->setType('returnurl', PARAM_LOCALURL);
 
         // Name.
-        $form->addElement('text', 'name', get_string('name', 'gradingform_guide'), array('size'=>52));
+        $form->addElement('text', 'name', get_string('name', 'gradingform_guide'),
+            array('size' => 52, 'maxlength' => 255));
         $form->addRule('name', get_string('required'), 'required');
         $form->setType('name', PARAM_TEXT);
+        $form->addRule('name', null, 'maxlength', 255, 'client');
 
         // Description.
         $options = gradingform_guide_controller::description_form_field_options($this->_customdata['context']);
diff --git a/grade/grading/form/guide/guideeditor.php b/grade/grading/form/guide/guideeditor.php
index da430ec9027..902834c5166 100644
--- a/grade/grading/form/guide/guideeditor.php
+++ b/grade/grading/form/guide/guideeditor.php
@@ -197,6 +197,10 @@ class moodlequickform_guideeditor extends HTML_QuickForm_input {
                     $errors['err_noshortname'] = 1;
                     $criterion['error_description'] = true;
                 }
+                if (strlen(trim($criterion['shortname'])) > 255) {
+                    $errors['err_shortnametoolong'] = 1;
+                    $criterion['error_description'] = true;
+                }
                 if (!strlen(trim($criterion['maxscore']))) {
                     $errors['err_nomaxscore'] = 1;
                     $criterion['error_description'] = true;
diff --git a/grade/grading/form/guide/lang/en/gradingform_guide.php b/grade/grading/form/guide/lang/en/gradingform_guide.php
index 6bbfb40a79e..a36eabc7df4 100644
--- a/grade/grading/form/guide/lang/en/gradingform_guide.php
+++ b/grade/grading/form/guide/lang/en/gradingform_guide.php
@@ -54,6 +54,7 @@ $string['err_nodescription'] = 'Student description can not be empty';
 $string['err_nodescriptionmarkers'] = 'Marker description can not be empty';
 $string['err_nomaxscore'] = 'Criterion max score can not be empty';
 $string['err_noshortname'] = 'Criterion name can not be empty';
+$string['err_shortnametoolong'] = 'Criterion name must be less than 256 characters';
 $string['err_scoreinvalid'] = 'The score given to {$a->criterianame} is not valid, the max score is: {$a->maxscore}';
 $string['gradingof'] = '{$a} grading';
 $string['guidemappingexplained'] = 'WARNING: Your marking guide has a maximum grade of <b>{$a->maxscore} points</b> but the maximum grade set in your activity is {$a->modulegrade}  The maximum score set in your marking guide will be scaled to the maximum grade in the module.<br />