Halo is a military science fiction franchise created by Bungie and now managed by 343 Industries. The series is centered around an interstellar war between humanity and an alliance of aliens known as the Covenant. The main protagonist, Master Chief, is a super-soldier known as a Spartan, who is tasked with defending humanity against overwhelming odds. The series began in 2001 with Halo: Combat Evolved on the original Xbox.

Halo is credited with revolutionizing the first-person shooter genre, particularly on consoles. Its engaging story, memorable characters, and innovative multiplayer modes have helped make it one of the most successful gaming franchises in history. Halo has spawned multiple sequels, spin-offs, and adaptations in other media, including books, comics, and television. Master Chief has become a symbol of the Xbox brand and a beloved character in gaming.