Violet Trefusis (née Keppel; 6 June 1894 – 29 February 1972) was an English writer and socialite. She is chiefly remembered for her lesbian affair with the poet Vita Sackville-West. She also wrote novels and many non-fiction works, both in English and French. The affair was featured in novels by both parties, and also in Virginia Woolf's Orlando: A Biography, as well as in many letters and memoirs of the period, roughly 1912-1922. Many are preserved at Yale University Library. Trefusis was an inspiration to many writers' fiction and was a pivotal character in their novels including Nancy Mitford's Love in a Cold Climate as "Lady Montdore" and in Harold Acton's The Soul's Gymnasium as "Muriel," a fictional portrait of her.
Born Violet Keppel, she was the daughter of Alice Keppel, later a mistress of King Edward VII of the United Kingdom, and her husband, The Hon. George Keppel, a son of the 7th Earl of Albemarle. Her biological father, however, was considered by members of the Keppel family to be William Beckett, subsequently 2nd Baron Grimthorpe, a banker and MP for Whitby.
Trefusis lived her early youth in London, where the Keppel family had a house in Portman Square. When Trefusis was four years old, Alice Keppel became the favourite mistress of Albert Edward (Bertie), the Prince of Wales, who became King Edward VII on 22 January 1901. He paid visits to the Keppel household in the afternoon around tea-time (while her husband, who was aware of the affair, was conveniently absent), on a regular basis until the end of his life in 1910.
In 1900 Trefusis' only sibling, Sonia (grandmother of Camilla, Duchess of Cornwall), was born. The current Duchess of Cornwall is thus her great-niece.