diff --git a/ext/dom/php_dom.h b/ext/dom/php_dom.h
index 7afbbf0442b..ad2fe2fec23 100644
--- a/ext/dom/php_dom.h
+++ b/ext/dom/php_dom.h
@@ -37,6 +37,7 @@ extern zend_module_entry dom_module_entry;
 #include <libxml/xmlerror.h>
 #include <libxml/xinclude.h>
 #include <libxml/hash.h>
+#include <libxml/c14n.h>
 #if defined(LIBXML_HTML_ENABLED)
 #include <libxml/HTMLparser.h>
 #include <libxml/HTMLtree.h>