diff --git a/include/nsysnet/socket.h b/include/nsysnet/socket.h
index 16b38f8b..6da99dd9 100644
--- a/include/nsysnet/socket.h
+++ b/include/nsysnet/socket.h
@@ -5,6 +5,7 @@
 #define FD_SETSIZE 32
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/select.h>
 
 /**
  * \defgroup nsysnet_socket Socket