diff --git a/lib/editor/tinymce/lib.php b/lib/editor/tinymce/lib.php
index 01537e912e7..10753a92a3d 100644
--- a/lib/editor/tinymce/lib.php
+++ b/lib/editor/tinymce/lib.php
@@ -178,6 +178,9 @@ class tinymce_texteditor extends texteditor {
             $params['valid_elements'] = 'script[src|type],*[*]'; // for some reason the *[*] does not inlcude javascript src attribute MDL-25836
             $params['invalid_elements'] = '';
         }
+        // Add unique moodle elements - unfortunately we have to decide if these are SPANs or DIVs.
+        $params['extended_valid_elements'] = 'nolink,tex,algebra,lang[lang]';
+        $params['custom_elements'] = 'nolink,~tex,~algebra,lang';
 
         if (empty($options['legacy'])) {
             if (isset($options['maxfiles']) and $options['maxfiles'] != 0) {