Lucas Malet was the pseudonym of Mary St Leger Kingsley (4 June 1852 - 1931), a Victorian novelist.
She was born in Eversley, Hampshire, the daughter of Charles Kingsley (author of The Water Babies). In 1876, she married William Harrison, Minor Canon of Westminster, and Priest-in-Ordinary to the Queen.
- Mrs Lorimer: A Study in Black and White (1882)
- Colonel Enderby's Wife (1885)
- Little Peter: A Christmas Morality for Children of Any Age (1888)
- A Counsel of Perfection (1888)
- The Wages of Sin (1890)
- The Carissima: A Modern Grotesque (1896)
- The Gateless Barrier (1900)
- The History of Sir Richard Calmady (1901), based on the life of Arthur MacMorrough Kavanagh
- The Far Horizon (1907)
- Adrian Savage (1911)
- Deadham Hard (1919)
- The Tall Villa (1920)
- The Survivors (1923)
- The Pool (1930)
She also completed her father's unfinished novel The Tutor's Story.