Monkeyman and O'Brien is an American science fiction creator-owned comics series created by artist Arthur Adams in 1993, which follows the adventures of Ann O'Brien, the daughter of a missing scientist, and Axwell Tiberius (the titular "Monkeyman", a 10-foot-tall (3.0 m) super-intelligent gorilla-like being from another dimension.
The series was published from 1993 to 1999 by Dark Horse Comics in various types of installments including short features in anthologies, backup stories in other series, a three issue limited series, a two issue crossover series (with the WildStorm team Gen13, published by Image Comics) and a comic strip in the promotional newspaper Dark Horse Extra.
In 1997, a trade paperback collection of four issues (the three issue limited series and a special consisting of the Hellboy: Seed of Destruction backups) was published.