diff --git a/src/gui/gui-hotlist.c b/src/gui/gui-hotlist.c
index 0b4a9ac5a..d7e6bf06a 100644
--- a/src/gui/gui-hotlist.c
+++ b/src/gui/gui-hotlist.c
@@ -27,6 +27,7 @@
 #endif
 
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 
 #include "../core/weechat.h"