1899–1900 was Celtic's twelfth season of competitive football.
They competed in the Scottish First Division, in which they ended runners-up.
[1] They won the Scottish Cup for the second season in a row, defeating Queen's Park 4-3.
It was the seventh major domestic competition won by Celtic.
Forward Sandy McMahon, who had been playing for the club since 1890, became the club's third ever captain, following Dan Doyle's retirement.