diff --git a/racket/src/rktio/rktio_network.c b/racket/src/rktio/rktio_network.c
index 3cc212a02d..6635309d8f 100644
--- a/racket/src/rktio/rktio_network.c
+++ b/racket/src/rktio/rktio_network.c
@@ -12,6 +12,7 @@
 # include <netinet/in.h>
 # include <netdb.h>
 # include <sys/socket.h>
+# include <sys/types.h>
 # include <fcntl.h>
 # include <errno.h>
 # define TCP_SOCKSENDBUF_SIZE 32768