Gustav Horn af Björneborg (1592–1657) was a Swedish/Finnish soldier and politician. He was the youngest son of Field Marshal Carl Horn. He was High Councillor of the realm in 1625, elevated to rank of field marshal in 1628, and sometimes commander-in-chief of Swedish forces in Germany during Thirty Years' War. He was instrumental in securing victory at the Battle of Breitenfeld in 1631. After the war, he served as Governor-General of Livonia 1652, President of War department and Lord High Constable in 1653. In 1651, Queen Christina created him Count of Pori.