The 1975 Five Nations Championship was the forty-sixth series of the rugby union Five Nations Championship. Including the previous incarnations as the Home Nations and Five Nations, this was the eighty-first series of the northern hemisphere rugby union championship. Ten matches were played between 18 January and 15 March. It was contested by England, France, Ireland, Scotland, and Wales. The championship was won by Wales, the team's eighteenth title (excluding another nine shared championships).