The 1966 All-Ireland Under-21 Football Championship was the third staging of the All-Ireland Under-21 Football Championship since its establishment by the Gaelic Athletic Association in 1964.
Kildare entered the championship as the defending champions.
On 2 October 1966, Roscommon won the championship following a 2âÂÂ10 to 1âÂÂ12 defeat of Kildare in the All-Ireland final. This was their first All-Ireland title.
Semi-finals
Final