diff --git a/examples/ostest/ostest_main.c b/examples/ostest/ostest_main.c
index 6d0ec4eeb..95f94b7c8 100644
--- a/examples/ostest/ostest_main.c
+++ b/examples/ostest/ostest_main.c
@@ -39,6 +39,7 @@
 
 #include <nuttx/config.h>
 
+#include <sys/wait.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>