Jan Costin Wagner (Langen, b. Oct 13th 1972 - ) is a German crime fiction writer. His novels are set in Finland and feature detective Kimmo Joentaa.
Wagner studied German Literature and History at university in Frankfurt, and later worked as a journalist. His first novel, "Nachtfahrt" (Night Trip) was published to much acclaim in 2002 and won the Marlowe Prize for Best Crime Novel. His wife is a native of Finland, and they spend time both there and in Germany.