diff --git a/jsmn.h b/jsmn.h
index 9174980..95fb2ca 100644
--- a/jsmn.h
+++ b/jsmn.h
@@ -1,6 +1,8 @@
 #ifndef __JSMN_H_
 #define __JSMN_H_
 
+#include <stddef.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif