Ailill Finn, son of Art mac Lugdach, was, according to medieval Irish legend and historical tradition, a High King of Ireland. In the Lebor Gabála Érenn, he succeeded to the throne when his father was killed by Fíachu Tolgrach and his son Dui Ladrach. He ruled for nine years. Two years into his reign, Fíachu Tolgrach was killed in battle against Airgetmar, son of Sírlám. The men of Munster, led by Ailill's son Eochu and Lugaid, son of Eochu Fíadmuine, then drove Airgetmar into exile overseas. After seven years Airgetmar returned to Ireland and killed Ailill with the help of Dui Ladrach and his son Fíachu, but was unable to seize the throne, which was taken by Eochu.