diff --git a/include/types.h b/include/types.h
index 483c894..870223e 100644
--- a/include/types.h
+++ b/include/types.h
@@ -1,5 +1,5 @@
-#ifndef _TYPES_H_
-#define _TYPES_H_
+#ifndef _SM64_TYPES_H_
+#define _SM64_TYPES_H_
 
 // This file contains various data types used in Super Mario 64 that don't yet
 // have an appropriate header.