Potamius (Greek: Ποτάμιος, fl. 343–360 AD), also known as Potamius of Lisbon, was the first recorded bishop of the city of Lisbon. He was possibly born in Lisbon, given that Iberian communities at the time usually chose their own citizens as bishops. He was part of the Council of Sirmium in 357, in which he defended Arianism. He is the second earliest Christian prose writer of the Iberian Peninsula, with Hosius of Corduba being the first.