The 1951 Five Nations Championship was the twenty-second series of the rugby union Five Nations Championship.

Including the previous incarnations as the Home Nations and Five Nations, this was the fifty-seventh series of the northern hemisphere rugby union championship.

Ten matches were played between 13 January and 7 April.

It was contested by England, France, Ireland, Scotland and Wales.

Ireland missed out on a second Grand Slam after drawing against Wales at Cardiff Arms Park, but won the championship.