Mercedes de Acosta (March 1, 1893 - 1968) was an American poet, playwright, costume designer, and socialite best known for her lesbian affairs with Greta Garbo, Marlene Dietrich, Alla Nazimova, Eva Le Galliene, Isadora Duncan, Katherine Cornell, Maude Adams, Ona Munson ("Belle Watling" in the movie "Gone With the Wind"), and others. It was a reputation not appreciated by everyone. As Alice B. Toklas wrote to a disapproving friend, Anita Loos, "You can't dispose of Mercedes lightly. She had the two most important women in U.S., Greta Garbo and Marlene Dietrich."

She was born a daughter of a Cuban father, Ricardo de Acosta and Spanish mother, Micaela Hernandez y de Alba, who was a descendant of the dukes of Alba, in New York City,

Mercedes de Acosta married, in 1920, Abram Poole (1882 - 1961), a noted painter and socialite. They divorced in 1935.

Her memoir, "Here Lies the Heart," was published in 1960. Its revelations, though highly sanitized, resulted in the severing of numerous friendships, including that of Greta Garbo. Cut off from many of her pals and increasingly in financial straits, Acosta died in relative poverty and obscurity. She is buried with her mother and sister Rita (see below) at Trinity Cemetery in Washington Heights in New York City.

Acosta's sister, Rita de Alba de Acosta, was a fabled beauty and aesthete best known as Rita Lydig.