The 1890–91 Scottish Cup was the 18th season of Scotland's most prestigious football knockout competition.
Heart of Midlothian defeated Dumbarton 1–0 to win the trophy.
Portland Lybster received a bye to the second round.
5th Kirkcudbright RV received a bye to the fourth round.
Abercorn, East Stirlingshire, Leith Athletic and 3rd Lanark RV received a bye to the quarter-finals.