Bandırma, port and town, northwestern Turkey, on the Sea of Marmara.
It was used in the 13th century by the Latin Crusaders as a base of operation against the Greeks of Asia Minor (Anatolia) and was taken by the Ottomans in the next century. Its protected harbour is now an active transit port between Istanbul and İzmir. A commercial centre, it exports the varied products of the hinterland, including cereals, sheep and cattle, grain, and boracite. Bandırma has road and rail connections with İzmir, Ankara, and Balıkesir. Lake Manyas, to the south, is a bird sanctuary and national park. Pop. (2000) 97,419; (2013 est.) 122,010.