Héctor Barrantes Sansoni (1939–1990) was an Argentine polo player. He was the stepfather of Sarah, Duchess of York.

He was a member of the patrician Figueroa family, and was born in 1939 in Argentina. He was the son of Martín Barrantes Figueroa y Arias and Clelia Josefina Sansoni Pais, both born in Salta, Argentina. The Figueroa family descended directly from Francisco de Toledo y Figueroa (10 July 1515 – 15 August 1582) who was an aristocrat and soldier of the Kingdom of Spain and the fifth Viceroy of Peru.^[1][2]

He started playing polo at the age of fifteen.^[2] In 1967, he moved to England to play polo with Samuel Vestey, 3rd Baron Vestey in Stowell Park.^[2][3] In 1983, he was barred from the international polo field for a year for a bout of anger.^[4]

Héctor Barrantes enlisted in the Argentine Army during the Falklands War of 1982 between Argentina and the United Kingdom, but did not fight.^[5]

Later, he bred polo ponies on his 1,000-acre (400 ha) ranch in Guaminí, 335 miles (540 km) southwest of Buenos Aires.^[2] His polo pony called Luna, which he bred on his ranch, won the Lady Townley Cup in 1989 and 1990, ridden by Gonzalo Pieres.^[6]

His first wife died in a car crash.^[2] In 1974, he started an affair with Susan Ferguson, the mother of Sarah Ferguson, who divorced her husband Major Ronald Ferguson and left her two daughters in England.^[2][4][7] In 1975, they married in a civil ceremony in Argentina.^[2] They resided on a polo ranch in Guaminí, Argentina.^[1][2]

He died of cancer in August 1990.^[1][2] He was buried, initially, in the Peace Garden cemetery in Buenos Aires.^[2] Later he was reinterred in a vault under his home and next to a polo field on his 'El Pucara' estate where, in 1998, his widow Susan was buried following her death, also from a car crash.^[8]

A major polo trophy in Argentina has been named in Barrantes's honour, the Copa Héctor Barrantes.^[9]