diff --git a/block_class.module b/block_class.module
index 48088e6..49a16b6 100644
--- a/block_class.module
+++ b/block_class.module
@@ -1,5 +1,17 @@
 <?php
 
+/**
+ * Implements hook_permission().
+ */
+function block_class_permission() {
+  return array(
+    'administer block classes' => array(
+      'title' => t('Administer block classes'),
+      'description' => t('Set CSS classes for blocks.'),
+    ),
+  );
+}
+
 /*
  * Extend block's classes with any user defined classes.
  */
@@ -41,7 +53,7 @@ function block_class($block) {
  * Alter block edit form
  */
 function block_class_form_alter(&$form, &$form_state, $form_id) {
-  if ($form_id == 'block_admin_configure' || $form_id == 'block_add_block_form') {
+  if (user_access('administer block classes') && $form_id == 'block_admin_configure' || $form_id == 'block_add_block_form') {
     $block = new stdClass;
     $block->module = $form['module']['#value'];
     $block->delta = $form['delta']['#value'];