diff --git a/lib/memdebug.h b/lib/memdebug.h
index addecef8f..87df8f297 100644
--- a/lib/memdebug.h
+++ b/lib/memdebug.h
@@ -28,6 +28,9 @@
 #include <sys/types.h>
 #endif
 
+#ifdef WIN32
+#include <winsock.h>
+#endif
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif