diff --git a/tests/libtest/lib1515.c b/tests/libtest/lib1515.c
index 943937a34..d5c8f7d08 100644
--- a/tests/libtest/lib1515.c
+++ b/tests/libtest/lib1515.c
@@ -35,6 +35,10 @@
 
 #define DNS_TIMEOUT 1
 
+#if defined(WIN32) || defined(_WIN32)
+#define sleep(s) Sleep(s * 1000)
+#endif
+
 static int debug_callback(CURL *curl, curl_infotype info, char *msg, size_t len, void *ptr)
 {
   (void)curl;