diff --git a/src/shrpx.cc b/src/shrpx.cc
index 4750c495..1f819d89 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -25,6 +25,7 @@
 #include "shrpx.h"
 
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <sys/stat.h>
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>