diff --git a/inc/rifle/types.h b/inc/rifle/types.h
index 6779b08..704c69b 100644
--- a/inc/rifle/types.h
+++ b/inc/rifle/types.h
@@ -1,6 +1,7 @@
 #ifndef RIFLE_TYPES_H
 #define RIFLE_TYPES_H
 
+#include <sys/types.h>
 #include <stdint.h>
 #include "rifle/token.h"