diff --git a/src/univ/textctrl.cpp b/src/univ/textctrl.cpp
index 0b71630f4c..6f94a7a76a 100644
--- a/src/univ/textctrl.cpp
+++ b/src/univ/textctrl.cpp
@@ -1684,7 +1684,7 @@ int wxTextCtrl::GetLineLength(wxTextCoord line) const
     }
     else // multiline
     {
-        if ( line < 0 || line >= GetLineCount() )
+        if ( line < 0 || (size_t)line >= GetLineCount() )
             return -1;
 
         return GetLines()[line].length();