Iarlaithe mac Loga, also known as Jarlath, was an Irish priest and scholar from Connacht, remembered as the founder of the monastic School of Tuam and of the Archdiocese of Tuam, of which he is the patron saint. No medieval biography of Jarlath is extant, but sources for his life and cult include genealogies, martyrologies, the Irish Lives of St Brendan of Clonfert, and a biography compiled by John Colgan in the 17th century.