diff --git a/c/qrcodegen.c b/c/qrcodegen.c
index 60d806c..d72b6ea 100644
--- a/c/qrcodegen.c
+++ b/c/qrcodegen.c
@@ -23,7 +23,6 @@
 
 #include <assert.h>
 #include <limits.h>
-#include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 #include "qrcodegen.h"
diff --git a/c/qrcodegen.h b/c/qrcodegen.h
index 9b37cee..ebb80d4 100644
--- a/c/qrcodegen.h
+++ b/c/qrcodegen.h
@@ -24,6 +24,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>