diff --git a/ext/dom/html5_serializer.c b/ext/dom/html5_serializer.c
index cd37b227739..215acb6da95 100644
--- a/ext/dom/html5_serializer.c
+++ b/ext/dom/html5_serializer.c
@@ -20,6 +20,7 @@
 
 #include "php.h"
 #if defined(HAVE_LIBXML) && defined(HAVE_DOM)
+#include "php_dom.h"
 #include "html5_serializer.h"
 #include "namespace_compat.h"
 #include "serialize_common.h"
diff --git a/ext/dom/namespace_compat.c b/ext/dom/namespace_compat.c
index 22442effa86..69991c1427f 100644
--- a/ext/dom/namespace_compat.c
+++ b/ext/dom/namespace_compat.c
@@ -20,6 +20,7 @@
 
 #include "php.h"
 #if defined(HAVE_LIBXML) && defined(HAVE_DOM)
+#include "php_dom.h"
 #include "namespace_compat.h"
 #include "internal_helpers.h"