diff --git a/core/msg.c b/core/msg.c
index e9086babb4..9ae2b9adf4 100644
--- a/core/msg.c
+++ b/core/msg.c
@@ -24,6 +24,7 @@
 #include <stddef.h>
 #include <irq.h>
 #include <cib.h>
+#include <inttypes.h>
 
 #include "flags.h"