Hitman (Tommy Monaghan) is a character appearing in American comic books published by DC Comics. The character was created by Garth Ennis and John McCrea and first appeared in The Demon Annual #2 before receiving his own series by Ennis and McCrea that ran for 61 issues.

Hitman chronicles the exploits of Tommy Monaghan, an ex-Marine Gulf War veteran turned contract killer from the Cauldron, a lower-class Irish district of Gotham City. He first appears in The Demon Annual #2 (part of the "Bloodlines" crossover in the summer of 1993), when he is attacked and bitten by a Bloodlines parasite called Glonth. Instead of dying, the bite unexpectedly triggers his metagene and grants him x-ray vision and moderate telepathy. A side effect is that his corneas and irises are solid black, indistinguishable from his pupils; the sight managed to unnerve Batman when he first saw them. The inherited powers later come with limits, and Monaghan uses them selectively, both because of the difficulty of concentrating during an explosive firefight and the side effects of their extended use (which includes anything between a headache and a minor illness).

After gaining these powers, Monaghan decides to specialize in killing metahumans and supernatural threats, targets typically shunned by conventional contract killers as too dangerous or too expensive. Despite his powers, Monaghan relies most on his creativity, improvisational abilities, and impressive gunfighting skills to take down a majority of his targets. This specialty line of work gives him an edge over his competition, but also leads him to encountering a number of eclectic characters including demons, zombies, dinosaurs, gods, superheroes and supervillains, as well as more conventional, realistic characters such as CIA agents, the SAS and the Mafia.

The series is firmly entrenched in the DC Universe. Batman, the Joker, Green Lantern, Catwoman, Etrigan, and Superman all guest star at various points, and joking references are frequently made to then-current DC happenings (such as the long-haired Superman). The series also crossed over with many DC events, including Final Night, One Million, and No Man's Land. Monaghan also teamed with Lobo and has made a few appearances outside the series.

Although the character adopts the moniker "Hitman" in his first appearance, the name is never used in his own series; the rest of the time, he is referred to by his given name (although he was sometimes called "Hitman" in guest appearances).

Hitman first appeared during Garth Ennis's run on The Demon during the "Bloodlines" crossover, and subsequently appeared in two further arcs before the series was cancelled. After making a brief appearance in a Batman comic, he got his own self-titled series.

Hitman was first published as a 60-issue comic book series with one annual, one DC One Million tie-in issue, one crossover with Lobo and one appearance in Sovereign Seven #26. Issues were more or less published monthly and most were 22 pages.

Several collections were published in trade paperback, but the second half of the series had initially never been collected. What collections that had been published were left to go out-of-print over the years. In July 2009, DC began reprinting the trades, from the beginning, with some variation.