The 1970 All-Ireland Under-21 Football Championship was the seventh staging of the All-Ireland Under-21 Football Championship since its establishment by the Gaelic Athletic Association in 1964. The championship ran from 5 April to 4 October 1970.
Antrim entered the championship as defending champions, however, they were beaten by Derry in the Ulster quarter-final.
The All-Ireland final was played on 4 October 1970 at Croke Park in Dublin, between Cork and Fermanagh, in what was their first ever meeting in the final. Cork won the match by 2-11 to 0-09 to claim their first ever All-Ireland U21 title.
Roscommon's Mickey Freyne was the championship's top scorer with 1-17.