The family name Whelan /ˈhwiːlən/ is an anglicisation of the Irish surname, Ó Faoláin. ... Therefore, the name Faelán, becomes "Úa Faeláin" as a patronym in Middle Irish, from which is derived "Ó Faoláin" in Modern Irish, of which in turn "Whelan", "Phelan", "O'Phelan" etc.