diff --git a/includes/theme.inc b/includes/theme.inc
index 4c454ba..7032bce 100644
--- a/includes/theme.inc
+++ b/includes/theme.inc
@@ -2479,7 +2479,7 @@ function template_preprocess_html(&$variables) {
   // mechanisms for extraction of this RDF content via XSLT transformation
   // using an associated GRDDL profile.
   $variables['rdf_namespaces']    = drupal_get_rdf_namespaces();
-  $variables['grddl_profile']     = 'http://www.w3.org/1999/xhtml/vocab';
+  $variables['grddl_profile']     = 'http://www.w3.org/1999/xhtml/vocab/';
   $variables['language']          = $GLOBALS['language'];
   $variables['language']->dir     = $GLOBALS['language']->direction ? 'rtl' : 'ltr';