diff --git a/mod/glossary/view.php b/mod/glossary/view.php
index 5d2dc533700..b20a98e8fb7 100644
--- a/mod/glossary/view.php
+++ b/mod/glossary/view.php
@@ -3,6 +3,7 @@
 /// This page prints a particular instance of glossary
 require_once("../../config.php");
 require_once("lib.php");
+require_once($CFG->libdir . '/completionlib.php');
 require_once("$CFG->libdir/rsslib.php");
 
 $id = optional_param('id', 0, PARAM_INT);           // Course Module ID