diff --git a/src/widgets/Notebook.hpp b/src/widgets/Notebook.hpp
index ac6c4dad7..23888ae61 100644
--- a/src/widgets/Notebook.hpp
+++ b/src/widgets/Notebook.hpp
@@ -2,6 +2,7 @@
 
 #include "widgets/BaseWidget.hpp"
 
+#include <ForwardDecl.hpp>
 #include <pajlada/signals/signal.hpp>
 #include <pajlada/signals/signalholder.hpp>
 #include <QList>