Rosa Lewis, née Ovenden (1867 – 1952) was a British chef, owner of the Cavendish Hotel in London, located at the intersection of Jermyn Street and Duke Street. Known as the "Queen of Cooks," Lewis was said to have had an affair with Edward VII in the 1890's. She was also called "The Duchess of Jermyn Street." The 1976-77 BBC television series, The Duchess of Duke Street, starring Gemma Jones, was loosely based on her life story. It is said that some of the scenes in Vile Bodies by Evelyn Waugh also were inspired by the Cavendish Hotel under Lewis' management, in which she appears as her fictional counterpart Lottie Crump.

Richard Hillary knew her, and wrote in The Last Enemy: Lewis died in her sleep on November 29, 1952 at the age of 85.