diff --git a/core/include/rmutex.h b/core/include/rmutex.h
index 6bf99efd7e..ef8c0692c6 100644
--- a/core/include/rmutex.h
+++ b/core/include/rmutex.h
@@ -21,6 +21,7 @@
 #ifndef RMUTEX_H
 #define RMUTEX_H
 
+#include <stdint.h>
 #include <stdatomic.h>
 
 #include "mutex.h"