Lily Dougall, British Canadian novelist and religious author, was born in Montreal, Canada on 16 April 1858, one of several siblings. Her father, John Dougall, was a Scottish immigrant who founded the evangelical newspaper Montreal Witness. Lily's mother, Elizabeth Redpath (d.1883), was the daughter of John Redpath (1796-1869), an immigrant from Berwickshire who became a wealthy Canadian businessman, sugar magnate, and philanthropist. In 1870, the Dougalls moved to New York to found the New York Witness but the panic of 1873 and subsequent failure of the paper led to both financial and emotional strain for the family.

In 1880, Lily went to stay with her aunt, Jane Redpath (d.1897), in Edinburgh and attended lectures on English Literature and Moral Philosophy, earning a 'higher certificate' from the Edinburgh Ladies Educational Association (at the time, women were not able to be admitted to the University of Edinburgh). After the death of her mother in 1883, Lily returned to Edinburgh and studied at the University of St Andrews via a correspondence course, becoming an LLA (lady literate in arts) in 1887.

Dougall's first novel, Beggars All, was well-received upon its publication in 1891. This was followed by nine more novels, including What Necessity Knows (1893), The Mermaid (1895), The Madonna of a Day (1895) and The Zeit-Geist (1895). For her historical novel, The Mormon Prophet (1898), Dougall researched the history of the Mormons in the archives at Salt Lake City, Utah. Dougall's novels were typically moralistic in tone, the strong female lead usually having to overcome an often bizarre moral dilemma. Dougall also wrote short stories for newspapers and magazines; her short story collection, A Dozen Ways of Love, was published in 1897.

In 1900, Dougall anonymously published her influential and successful non-fiction work, Pro Christo et Ecclesia. This was followed by further works on religion, including Absente Reo in 1910 and The Practice of Christianity in 1913, which were also published anonymously and called for church reform and social change.

Dougall's long-term companion was Mary Sophia 'Sophie' Earp (c.1865-1928), an early graduate of Newnham College, Cambridge. Having originally settled in Exmouth upon Dougall's return to England in 1903, they moved to Cutts End in Cumnor near Oxford in 1911. Dougall was part of the Anglican modernist movement and the house in Cumnor soon became the setting of many meetings of the 'Cumnor Group' of clerics, academics, and writers, including Canon Burnett Hillman Streeter (1874-1937) of Queen's College, Oxford and Arthur Clutton-Brock (1868-1924). Alongside writing for various journals and newspapers, Dougall collaborated with Streeter and others on 'group-books' including Immortality (1917). Dougall also became involved with the Anglican Fellowship, The Guild of Health and the Student Christian Movement. In 1919, she published a volume of light verse with Gilbert Sheldon entitled Arcades Ambo.

Dougall died on 9 October 1923. After her death, Sophie and Canon Streeter hoped to compile a memoir of Dougall's life, but this was never completed. Sophie died in 1928 and was buried alongside Dougall in the graveyard of St Michael's Church, Cumnor.