diff --git a/winpr/include/winpr/wlog.h b/winpr/include/winpr/wlog.h
index f7d7ec0c1..7da8aa51a 100644
--- a/winpr/include/winpr/wlog.h
+++ b/winpr/include/winpr/wlog.h
@@ -27,6 +27,7 @@
 extern "C" {
 #endif
 
+#include <stdarg.h>
 #include <winpr/wtypes.h>
 #include <winpr/synch.h>
 #include <winpr/thread.h>