Baron Gustav Evertsson Horn of Marienburg (May 28, 1614 – February 27, 1666) was a Finnish-Swedish military and politician. He was a member of the Privy Council of Sweden and Governor General.Horn, the son of Field Marshal Evert Horn, was born in 1614 in Southwest Finland, at the time a part Sweden. He became captain in 1635, and a colonel in 1640. In 1651, he was, along with cousin Henrik Horn, raised to a baron.