The 1890–91 season was the third season of football by Celtic, this marked the first season where Celtic took part in the newly formed Scottish Football League, they also competed in the Scottish Cup, Scottish League Charity Competition and Glasgow Cup.
Source: [1] Rules for classification: 1) Points; (C) Champions Notes:
^ abDumbarton and Rangers finished equal on points, and a play-off to determine the winner ended in a 2−2 draw so both teams were declared joint champions.
^ abCeltic, 3rd LRV and Cowlairs were deducted four points each for fielding ineligible players.