diff --git a/arch/sim/src/up_initialize.c b/arch/sim/src/up_initialize.c
index fcfe9d24b0..7eb49cb1fa 100644
--- a/arch/sim/src/up_initialize.c
+++ b/arch/sim/src/up_initialize.c
@@ -41,6 +41,7 @@
 #include <sys/types.h>
 #include <nuttx/arch.h>
 #include <nuttx/fs.h>
+#include <debug.h>
 #include "up_internal.h"
 
 /****************************************************************************