diff --git a/h2o.php b/h2o.php
index 25f7ac0..347cc3b 100644
--- a/h2o.php
+++ b/h2o.php
@@ -10,6 +10,7 @@
 require H2O_ROOT.'h2o/errors.php';
 require H2O_ROOT.'h2o/filters.php';
 require H2O_ROOT.'h2o/context.php';
+require H2O_ROOT.'h2o/parser.php';
 
 /**
  * Example: