Cathryn Mary Lee Harrison (born 25 May 1959) is an English actress. She is the daughter of the actor and singer Noel Harrison and Sara Lee Eberts and the granddaughter of actor Sir Rex Harrison. Her siblings, Simon and Harriet Harrison are also in the acting profession. Cathryn Harrison has half-siblings from her father's second marriage, Will and Chloe, and an older half-sister, Zoe, from her mother's first marriage to Carleton John Richard Tufnell. In May 1996 she married Paul Laing. Her uncle is playwright and activist Carey Harrison.

Harrison began her career with Robert Altman's film Images in 1972. Her later performances include the role of Lily in Black Moon (1975), Louis Malle's first film in English, as well as many television programmes including Portrait of a Marriage (1990) in which she played Violet Trefusis, Vita Sackville West's lesbian lover.

She has worked in British television and radio dramas. She appeared in Love on a Branch Line and a 1977 Australian film called Blue Fire Lady. She also appeared as Major Tom Cadman's wife in the ITV series Soldier Soldier, and played assistant stage manager Irene in the film version of Ronald Harwood's The Dresser.