diff --git a/lang/c++/api/Zigzag.hh b/lang/c++/api/Zigzag.hh
index bf831d24..7ce5c2cf 100644
--- a/lang/c++/api/Zigzag.hh
+++ b/lang/c++/api/Zigzag.hh
@@ -20,6 +20,7 @@
 #define avro_Encoding_hh__
 
 #include <stdint.h>
+#include <stddef.h>
 #include <array>
 
 #include "Config.hh"