Rathmullan (Gaelic: Ráth Maoláin, meaning "Maoláin's ringfort") is a small seaside village on the Fanad Peninsula in County Donegal, Ireland. It is situated on the western shore of Lough Swilly, 11 km north-east of Ramelton and 12 km east of Milford. Rathmullan was the scene of the Flight of the Earls in 1607.
There are also the ruins of a medieval Carmelite Friary in Rathmullan which was built by Eoghan Rua MacSweeney in 1516. The Friary was sacked by the English garrison from Sligo in 1595. In 1607, Rathmullan was also said to have seen the last of the Gaelic Order, most notably the Clan Ó Néill and the Clan Ó Domhnaill, during the Flight of the Earls to the Continent. This 'flight' took place from Portnamurray on the southern edge of the town. In 1617 the Friary was occupied by the Protestant Bishop of Raphoe, The Rt. Rev. Dr. Andrew Knox, who turned it into a stronghold during the colonisation of County Donegal during the Plantation of Ulster.
Rathmullan beach is one of the finest beaches in Donegal if not the whole of Ireland. The beach is safe for swimming and water sports. There is also a Sailing and Water Sports School which operates on the beach.