diff --git a/src/proxyface/proxyauth.hxx b/src/proxyface/proxyauth.hxx
index 6226a9d..5c2b503 100644
--- a/src/proxyface/proxyauth.hxx
+++ b/src/proxyface/proxyauth.hxx
@@ -9,7 +9,11 @@
 #define __PROXYAUTH_HXX__
 
 #include <proxyface/ui_proxyauth.hxx>
-#include <QDialog>
+#if QT_VERSION >= 0x050000
+#include <QtWidgets/QDialog>
+#else
+#include <QtGui/QDialog>
+#endif
 
 class ProxyAuth: public QDialog, public Ui::ProxyAuth {
     Q_OBJECT