The 1984 All-Ireland Under-21 Football Championship was the 21st staging of the All-Ireland Under-21 Football Championship since its establishment by the Gaelic Athletic Association in 1964.
Mayo entered the championship as defending champions.
On 26 August 1984, Cork won the championship following a 0âÂÂ9 to 0âÂÂ6 defeat of Mayo in the All-Ireland final. This was their fifth All-Ireland title overall and their first in three championship seasons.
Semi-finals
Finals