John Farrelly (c.1969 - 31 October 2025) was an Irish comic artist, caricaturist, illustrator and author, best known for the Deadly Irish History series published by O'Brien Press.

In the 1990s he was part of the teams behind the Northern Irish anthologies NutScrewsWashersNBolts and DNA Swamp, for which he created the 'Long Coat and Leather Jacket' series. He later drew for the small-press titles Splank! and Sector 13, and for the 2000AD fanzine Zarjaz. His own webcomic, Captain Wonder - about a middle-aged man who dons a costume to save his beloved comic shop - was self-published as two issues, and earlier in 2025 he achieved a long-held ambition when VIZ published his strip 'Beverly Hills Shop'.

He self-published a zombie novel set during the American Civil War, The Legend of Navin Holt - Zombie Hunter, and wrote and illustrated three heavily illustrated histories for O'Brien Press - The Celts, The Vikings and The Normans - which used text, cartoons and comic strips to fool children into learning some history. His last book, Farrelly's Field Guide to Irish Faerie Folk (2024), is a guide to the strange magical creatures of Ireland drawn in a vintage gothic style, and contains some of his best illustration work.

He died at the Evora Hospice in Newry on 31 October 2025, a month after being diagnosed with terminal cancer.