diff --git a/libmetal/lib/system/zephyr/mutex.h b/libmetal/lib/system/zephyr/mutex.h
index bfe689f..6ab20d4 100644
--- a/libmetal/lib/system/zephyr/mutex.h
+++ b/libmetal/lib/system/zephyr/mutex.h
@@ -29,7 +29,7 @@ typedef struct k_sem metal_mutex_t;
  * METAL_MUTEX_INIT - used for initializing an mutex elmenet in a static struct
  * or global
  */
-#define METAL_MUTEX_INIT(m) _K_SEM_INITIALIZER(m, 1, 1)
+#define METAL_MUTEX_INIT(m) Z_SEM_INITIALIZER(m, 1, 1)
 /*
  * METAL_MUTEX_DEFINE - used for defining and initializing a global or
  * static singleton mutex