David John Nicoll (8 December 1859 – 2 March 1919) was a British anarchist newspaper editor, writer, poet and public speaker.

[8] At the 1890 annual conference of the Socialist League, William Morris was ousted as editor of Commonweal and was replaced by Nicoll and Frank Kitz with Charles Mowbray as publisher.

"[12] From 1892 Nicoll used his platform to take a leading role in supporting the defence of the Walsall anarchists – a group charged with manufacturing explosives.

Nicoll and Commonweal's publisher Charles Mowbray were arrested for incitement to murder Matthews, Hawkins and Melville.

[15][16] The prosecutor in the trial was the Attorney General Sir Richard Webster, while Nicoll chose to defend himself, later publishing his closing speech as a pamphlet.

In 1897 Nicoll authored and self-published the pamphlet The Greenwich Mystery: Letters from the Dead about the death of Martial Bourdin, in which he accused Samuels of being a police spy.

The pamphlet is believed to have heavily influenced Joseph Conrad's novel The Secret Agent and Olivia Rossetti Agresti's fictionalised memoir A Girl Among the Anarchists (written under the pen name Isabel Meredith).

[27][28] Nicoll spent the rest of his life in poverty, suffering poor mental health, working as a street vendor and selling pamphlets.