diff --git a/ext/libxml/ruby_xml_reader.c b/ext/libxml/ruby_xml_reader.c
index 6da099a2..37e35fbd 100644
--- a/ext/libxml/ruby_xml_reader.c
+++ b/ext/libxml/ruby_xml_reader.c
@@ -4,6 +4,8 @@
 #include "ruby_libxml.h"
 #include "ruby_xml_reader.h"
 
+#include <errno.h>
+
 #include <libxml/xmlreader.h>
 #include <libxml/xmlschemas.h>