diff --git a/Userland/Libraries/LibC/syslog.h b/Userland/Libraries/LibC/syslog.h
index eedebdc277..c23597a7d9 100644
--- a/Userland/Libraries/LibC/syslog.h
+++ b/Userland/Libraries/LibC/syslog.h
@@ -27,6 +27,7 @@
 #pragma once
 
 #include <stdarg.h>
+#include <sys/cdefs.h>
 
 __BEGIN_DECLS