diff --git a/python/libxml_wrap.h b/python/libxml_wrap.h
index 56950e9..d1c5dc9 100644
--- a/python/libxml_wrap.h
+++ b/python/libxml_wrap.h
@@ -18,6 +18,7 @@
 #include <libxml/xmlregexp.h>
 #include <libxml/xmlautomata.h>
 #include <libxml/xmlreader.h>
+#include <libxml/relaxng.h>
 
 /**
  * ATTRIBUTE_UNUSED: