The Scottish Seafishers' Union was a trade union representing fishermen in Scotland. The union was founded in 1899 as the Aberdeen Steam Fishing Vessels Enginemen's and Firemen's Union. It had 200 members by the end of the year, but this declined to only 60 in 1903, when Joseph Forbes Duncan was appointed as general secretary. Within the year, he had increased membership to 360, and from 1905 began opening branches around Scotland. As a result, the union's named was changed to the Scottish Steam Fishing Vessels' Enginemen and Firemen's Union.