Ailill mac Cathail Con-cen-máthair (died 701)^[1] was a King of Munster from the Glendamnach branch of the Eóganachta. He was the son of Cathal Cú-cen-máthair mac Cathail (d. 665) and brother of his predecessor Finguine mac Cathail Con-cen-máthair (d. 696).^[2]

Though mentioned in the annals as king^[3] and in the saga Senchas Fagbála Caisil "The Story of the Finding of Cashel",^[4] he is omitted from lists in the Laud Synchronisms and the Book of Leinster.^[5] Also in the list of signatories to the signing of Adomnan's Law of the Innocents at Birr in 697; he is only mentioned as king of Mag Feimin while Eterscél mac Máele Umai (d. 721) is named king of Munster.

Ailil had three sons: Fogantach, Aonghus and Dubhda but none of his descendants were kings.