diff --git a/src/richtext/richtextxml.cpp b/src/richtext/richtextxml.cpp
index 1df105a391..e7f20cd917 100644
--- a/src/richtext/richtextxml.cpp
+++ b/src/richtext/richtextxml.cpp
@@ -361,7 +361,7 @@ static void OutputStringEnt(wxOutputStream& stream, const wxString& str,
             }
             last = i + 1;
         }
-        else if (c > 127)
+        else if ((unsigned wxChar)c > 127)
         {
             OutputString(stream, str.Mid(last, i - last), convMem, convFile);