John Stephen Farmer (7 March 1854 – 18 January 1916) also known as J. S. Farmer was a British lexicographer, spiritualist and writer.

His lifetime work was Slang and its Analogues published in seven volumes (1890–1904) with William Ernest Henley.

[1][2] Farmer took interest in psychical research and spiritualism.

[3] From 1878, he also edited the Psychological Review, a spiritualist periodical.

[4] Farmer was a member of the London Spiritualist Alliance.