diff --git a/lib/Doctrine/ORM/Query/QueryException.php b/lib/Doctrine/ORM/Query/QueryException.php
index 8d801b1d3f7..18398748522 100644
--- a/lib/Doctrine/ORM/Query/QueryException.php
+++ b/lib/Doctrine/ORM/Query/QueryException.php
@@ -117,7 +117,7 @@ public static function invalidParameterFormat($value)
      */
     public static function unknownParameter($key)
     {
-        return new self('Invalid parameter: token ' . $key . ' is not defined in the query.');
+        return new self('Invalid parameter: token "' . $key . '" is not defined in the query.');
     }
 
     /**