diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index b455021c2fd..36920f7f863 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -240,7 +240,7 @@ if_indextoname(index) -- return the corresponding interface name\n\
 # include <ctype.h>
 #endif
 
-#if defined(__APPLE__) || defined(__NetBSD__)
+#if defined(__APPLE__) || defined(__CYGWIN__) || defined(__NetBSD__)
 # include <sys/ioctl.h>
 #endif