diff --git a/gtk/gtk-autocleanups.h b/gtk/gtk-autocleanups.h
index 089dd0a735..8eae230f44 100644
--- a/gtk/gtk-autocleanups.h
+++ b/gtk/gtk-autocleanups.h
@@ -66,7 +66,6 @@ G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkColorChooserWidget, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkComboBox, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkComboBoxText, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkCssProvider, g_object_unref)
-G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkDialog, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkDrawingArea, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkEditable, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkEntry, g_object_unref)
diff --git a/gtk/gtkdialog.h b/gtk/gtkdialog.h
index 87b4678196..9474f0d1c6 100644
--- a/gtk/gtkdialog.h
+++ b/gtk/gtkdialog.h
@@ -25,14 +25,12 @@
 #ifndef __GTK_DIALOG_H__
 #define __GTK_DIALOG_H__
 
-
 #if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
 #error "Only <gtk/gtk.h> can be included directly."
 #endif
 
 #include <gtk/gtkwindow.h>
 
-
 G_BEGIN_DECLS
 
 /**
@@ -208,6 +206,10 @@ GtkWidget * gtk_dialog_get_content_area (GtkDialog *dialog);
 GDK_AVAILABLE_IN_3_12
 GtkWidget * gtk_dialog_get_header_bar   (GtkDialog *dialog);
 
+#ifndef __GI_SCANNER__
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GtkDialog, g_object_unref)
+#endif
+
 G_END_DECLS
 
 #endif /* __GTK_DIALOG_H__ */