diff --git a/include/lib/fconf/fconf.h b/include/lib/fconf/fconf.h
index 917e053..131c542 100644
--- a/include/lib/fconf/fconf.h
+++ b/include/lib/fconf/fconf.h
@@ -7,6 +7,7 @@
 #ifndef FCONF_H
 #define FCONF_H
 
+#include <stddef.h>
 #include <stdint.h>
 
 /* Public API */