The 1971 All-Ireland Under-21 Football Championship was the eighth staging of the All-Ireland Under-21 Football Championship since its establishment by the Gaelic Athletic Association in 1964.
Cork entered the championship as defending champions.
On 19 September 1971, Cork won the championship following a 3-10 to 0-3 defeat of Fermanagh in the All-Ireland final. This was their second All-Ireland title overall and their second in succession.