diff --git a/sys/include/uart_stdio.h b/sys/include/uart_stdio.h
index aed349dd92..2154b31ba0 100644
--- a/sys/include/uart_stdio.h
+++ b/sys/include/uart_stdio.h
@@ -21,6 +21,7 @@
 #define UART_STDIO_H
 
 /* Boards may override the default STDIO UART device */
+#include <stdint.h>
 #include "board.h"
 
 #ifdef __cplusplus