Madlax (マドラックス, Madorakkusu) is a 26-episode Japanese anime television series produced in 2004 by the Bee Train animation studio. Kōichi Mashimo directed Madlax and the soundtrack was composed by Yuki Kajiura. The DVD version was released by ADV Films in North America and the United Kingdom and by Madman Entertainment in Australia and New Zealand.

The story revolves around the two young women Margaret and Madlax, who seemingly have little in common and do not know of the other's existence at the beginning. Madlax is a legendary mercenary and assassin in the fictional civil war-torn country of Gazth-Sonika, who cannot remember her past or indeed her real name before twelve years ago, when the war started. The other main character is Margaret Burton, the sole heir of a wealthy aristocratic family in the peaceful European country Nafrece. Twelve years before the story begins, an airliner Margaret and her mother were on crashed over Gazth-Sonika, and its passengers, as well as Margaret's father who led the rescuers, have been missing ever since. Margaret, however, mysteriously traveled back to Nafrece on her own, losing her memories prior to her return; the only thing she recalls is a single word, "Madlax". With this thread linking the two girls, they both independently start investigating the powerful crime syndicate Enfant after its enigmatic mastermind shows interest in both of them.

Madlax was produced as a spiritual successor to the studio's earlier project, Noir, and together with El Cazador de la Bruja, these series constitute a trilogy exploring the "girls-with-guns" genre. The production of Madlax began in 2002 but it wasn't until Yōsuke Kuroda joined the project that the series took its final form. While the critics noted the resulting similarities between Noir and Madlax, they also acknowledged the differences, such as the latter's less episodic and more plot-driven style and, in particular contrast to the predominantly realistic Noir, incorporation of many supernatural elements, which the audience must often interpret without further explanation.