Antoinette Corisande Élisabeth, Duchess of Clermont-Tonnerre (néede Gramont; 23 April 1875 – 6 December 1954) was a French writer of the early 20th century, best known for her long-term lesbian relationship with Natalie Clifford Barney. A descendant of Henry IV of France, Élisabeth de Gramont had grown up among the highest aristocracy; when she was a child, according to Janet Flanner, "peasants on her farm... begged her not to clean her shoes before entering their houses". She looked back on this lost world of wealth and privilege with little regret, and became known as the "red duchess" for her support of socialism.
She was a close friend, and sometimes critic of writer Marcel Proust, whom she had met on 9 June 1903. In her youth, Élisabeth de Gramont was a strikingly pretty woman. Opinionated, outspoken, she became openly bisexual by the start of the 20th century, despite being married.