diff --git a/libavcodec/snow_dwt.h b/libavcodec/snow_dwt.h
index 6ac49e2b9e..e2d7528056 100644
--- a/libavcodec/snow_dwt.h
+++ b/libavcodec/snow_dwt.h
@@ -21,6 +21,7 @@
 #ifndef AVCODEC_SNOW_DWT_H
 #define AVCODEC_SNOW_DWT_H
 
+#include <stddef.h>
 #include <stdint.h>
 
 typedef int DWTELEM;