diff --git a/gtk/gtkassistant.c b/gtk/gtkassistant.c
index 48d8506617..7e3a458b84 100644
--- a/gtk/gtkassistant.c
+++ b/gtk/gtkassistant.c
@@ -1612,10 +1612,14 @@ gtk_assistant_get_nth_page (GtkAssistant *assistant,
   GList *elem;
 
   g_return_val_if_fail (GTK_IS_ASSISTANT (assistant), NULL);
+  g_return_val_if_fail (page_num >= -1, NULL);
 
   priv = assistant->priv;
 
-  elem = g_list_nth (priv->pages, page_num);
+  if (page_num == -1)
+    elem = g_list_last (priv->pages);
+  else
+    elem = g_list_nth (priv->pages, page_num);
 
   if (!elem)
     return NULL;