diff --git a/libc/stdio/lib_libvsprintf.c b/libc/stdio/lib_libvsprintf.c
index a103b0c4eea..21219849e6d 100644
--- a/libc/stdio/lib_libvsprintf.c
+++ b/libc/stdio/lib_libvsprintf.c
@@ -39,6 +39,7 @@
 
 #include <nuttx/compiler.h>
 
+#include <wchar.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdio.h>