diff --git a/source/blender/src/buttons_editing.c b/source/blender/src/buttons_editing.c
index 377555597cf..3be7bd6cd52 100644
--- a/source/blender/src/buttons_editing.c
+++ b/source/blender/src/buttons_editing.c
@@ -33,6 +33,7 @@
 #include <time.h>
 #include <math.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 
 #ifdef WIN32