Katherine Cecil Thurston (18 April 1875 - 5 September 1911) was an Irish novelist.Born Katherine Cecil Madden in Cork, Ireland, the only daughter of banker Paul J. Madden (who was Mayor of Cork 1885-1886, and a friend of Charles Stuart Parnell) and Catherine Madden (born Barry), she was privately educated. By the end of the 19th century she was contributing short stories to various British and American publications, such as Pall Mall Magazine, Blackwood's Edinburgh Magazine, Harper's Magazine, Windsor Magazine and others.
In 1901, she married the writer Ernest Temple Thurston (1879-1933). They separated in 1907 and were divorced in 1910 on grounds of his adultery and desertion. The suit went undefended. Thurston "complained that she was making more money by her books than he was, that her personality dominated his, and had said that he wanted to leave her.