diff --git a/src/gtk/textctrl.cpp b/src/gtk/textctrl.cpp
index 1443e57779..b9671b2850 100644
--- a/src/gtk/textctrl.cpp
+++ b/src/gtk/textctrl.cpp
@@ -943,6 +943,10 @@ bool wxTextCtrl::PositionToXY(long pos, long *x, long *y ) const
     if ( m_windowStyle & wxTE_MULTILINE )
     {
         GtkTextIter iter;
+
+        if (pos > GetLastPosition())
+            return false;
+
         gtk_text_buffer_get_iter_at_offset(m_buffer, &iter, pos);
 
         if ( y )