diff --git a/src/yes.c b/src/yes.c
index 56dbffe19..1fb87fd8f 100644
--- a/src/yes.c
+++ b/src/yes.c
@@ -19,6 +19,7 @@
 
 #include <config.h>
 #include <stdio.h>
+#include <sys/types.h>
 #include <getopt.h>
 
 #include "system.h"