Celtic went into the 2002–03 season defending their Scottish Premier League title, which they won in 2001–02.

[1] Celtic went into third qualifying stage of the Champions League but failed to beat Basel.

They then dropped down into the UEFA Cup where they beat teams including Blackburn Rovers, Stuttgart and Liverpool to reach the final where they lost 2–3 after extra time to Porto.

Celtic reached the final of the Scottish League Cup, but a late penalty miss by John Hartson meant the trophy went to Rangers.

As the number of games to be played took its toll, an inexperienced Celtic side lost to Inverness CT in the Scottish Cup.