diff --git a/src/frontends/qt4/GuiApplication.h b/src/frontends/qt4/GuiApplication.h
index 3d5b2d2d0f..79da314620 100644
--- a/src/frontends/qt4/GuiApplication.h
+++ b/src/frontends/qt4/GuiApplication.h
@@ -19,10 +19,6 @@
 #include <QList>
 
 class QAbstractItemModel;
-class QIcon;
-class QObject;
-class QSessionManager;
-class QSortFilterProxyModel;
 
 namespace lyx {