diff --git a/ixwebsocket/IXNetSystem.h b/ixwebsocket/IXNetSystem.h
index c7f376a4..b6c3b9d1 100644
--- a/ixwebsocket/IXNetSystem.h
+++ b/ixwebsocket/IXNetSystem.h
@@ -8,6 +8,10 @@
 
 #include <cstdint>
 
+#ifdef __FreeBSD__
+#include <sys/types.h>
+#endif
+
 #ifdef _WIN32
 
 #ifndef WIN32_LEAN_AND_MEAN