Ailill Flann Bec, son of
Fiachu Muillethan, was an
Irish dynast belonging to the
Deirgtine, the proto-historical ancestors of the historical
Eóganachta dynasties of
Munster. He was the father of Luigthech, also known as Lugaid, and thus the grandfather of
Conall Corc. Another son of Ailill Flann Bec may have been
Dáire Cerbba, but there is evidence against this.