diff --git a/YACReaderLibrary/server/requestmapper.h b/YACReaderLibrary/server/requestmapper.h
index 4bccc45b..98702789 100644
--- a/YACReaderLibrary/server/requestmapper.h
+++ b/YACReaderLibrary/server/requestmapper.h
@@ -7,6 +7,7 @@
 #define REQUESTMAPPER_H
 
 #include "httprequesthandler.h"
+#include <QMutex>