Björkö (Swedish for "Birch Island") may refer to:
Places Sweden Björkö, Ekerö, a Lake Mälaren island in Ekerö Municipality, Stockholm County, the location for the World Heritage Site Birka Björkö, Öckerö, an island in Öckerö Municipality, Västra Götaland County Björkö, Haninge, an island in Haninge Municipality, Stockholm County Björkö, the southern part of Väddö island in northern Roslagen, Norrtälje Municipality, Stockholm County. (Also a former parish there.) Björkö, Västervik, an island in Västervik Municipality, Kalmar County
Finland Björkö, Houtskär, one of the main islands of the former municipality Houtskär in the Archipelago Sea Björkö (Korsholm), a Kvarken island in Korsholm Municipality, Ostrobothnia Björkö, Kumlinge, an island and a village in Kumlinge Municipality in the Åland Islands Björkö, Korpo, an island in the former municipality Korpo in the Archipelago Sea
Russia The Swedish name for Primorsk, Leningrad Oblast and the Beryozovye Islands in the Leningrad Oblast
History The Treaty of Björkö, signed by Nicholas II of Russia and William II of the German Empire in 1905 and named after Björkö (now the Beryozovye Islands)