diff --git a/ssl.c b/ssl.c
index 78ab9e4..768f304 100644
--- a/ssl.c
+++ b/ssl.c
@@ -34,7 +34,11 @@
 #include "async.h"
 
 #include <assert.h>
+#ifdef _WIN32
+#include <windows.h>
+#else
 #include <pthread.h>
+#endif
 #include <errno.h>
 #include <string.h>