Copsig (also known as Copsi) was a Northumbrian magnate in late Anglo-Saxon England. He was a supporter of Tostig and was exiled along with him in 1065. He fled to Orkney, then part of Norway. He returned in 1066 and joined Tostig at Sandwich in Kent with 17 ships. He survived Tostig's defeat at Stamford Bridge and when William the Conqueror prevailed at Hastings, he went down in March 1067 to Barking where William was staying while his tower was being constructed in London and did homage. In return, William made him Earl of Northumbria and sent him back to Jorvik. He lasted five weeks before he was murdered by Osulf, son of Earl Eadulf III of the ancient Bernician family which had once ruled from Bamburgh, at Newburn-upon-Tyne. Osulf ruled as earl until the Autumn.