1902–03 was the 15th season of competitive football for Celtic, who competed in the Scottish First Division.
[1] For the third season in a row, Celtic failed to add major honours to their tally as they finished 5th in the league and were eliminated from the Scottish Cup in the 3rd round following a 0-3 home defeat to Rangers.
This was the last season at the club for captain Sandy McMahon, who would briefly play for fellow Glasgow club Partick Thistle before retiring.
Celtic won the Glasgow Charity Cup.