diff --git a/rtl/unix/unixcp.pp b/rtl/unix/unixcp.pp
index 532d9322d5..63bd64893a 100644
--- a/rtl/unix/unixcp.pp
+++ b/rtl/unix/unixcp.pp
@@ -714,7 +714,7 @@ var
 begin
   // Get one of non-empty environment variables in the next order:
   // LC_ALL, LC_CTYPE, LANG. Default is UTF-8 or ASCII.
-{$if defined(linux) or defined(darwin)}
+{$if defined(linux) or defined(darwin) or defined(haiku)}
   Result:=CP_UTF8;
 {$else}
   Result:=CP_ASCII;