diff --git a/event.c b/event.c
index 5586cd3..a67ca54 100644
--- a/event.c
+++ b/event.c
@@ -40,6 +40,9 @@
 #include <stddef.h>
 #include <stdlib.h>
 #include <assert.h>
+#ifdef _WIN32
+#include <winsock2.h>
+#endif
 
 #ifdef EV_EVENT_H
 # include EV_EVENT_H