diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index d8662c0554..6e0aee5ae5 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -1928,7 +1928,7 @@ wxString wxTextCtrl::GetLineText(long lineNo) const
 
         // remove the '\n' at the end, if any (this is how this function is
         // supposed to work according to the docs)
-        if ( buf[len - 1] == wxT('\n') )
+        if ( len && buf[len - 1] == wxT('\n') )
         {
             len--;
         }