diff --git a/lib/timeval.c b/lib/timeval.c
index 11f3d7a06..ce866ca82 100644
--- a/lib/timeval.c
+++ b/lib/timeval.c
@@ -26,6 +26,7 @@
 #ifndef HAVE_GETTIMEOFDAY
 
 #ifdef WIN32
+#include <windows.h>
 #include <mmsystem.h>
 
 static int gettimeofday(struct timeval *tp, void *nothing)