diff --git a/utf8.h b/utf8.h
index bff3909..4b19d64 100644
--- a/utf8.h
+++ b/utf8.h
@@ -1,6 +1,8 @@
 #ifndef UTF8_H
 #define UTF8_H
 
+#include <stdint.h>
+
 extern int locale_is_utf8;
 
 /* is c the start of a utf8 sequence? */