Justice League: War is a 2014 American animated superhero film featuring the DC Comics superhero team the Justice League, and an adaptation of the story Justice League: Origin by Geoff Johns and Jim Lee, the first story in DC's 2011 DC Universe relaunch. It was directed by Jay Oliva and scripted by Heath Corson. It is the 19th film of the DC Universe Animated Original Movies and the second film in the DC Animated Movie Universe. The film was released for downloading on January 21, 2014 and was released on Blu-ray and DVD formats on February 4. It had its world premiere at the Paley Center for Media on the same day. Warner Home Video re-released the film on a combo pack in August 2015, which includes a DVD and Blu-Ray copy, a digital copy, and the graphic novel it is based on. The film depicts an invasion of Earth by the alien and demon "New God", Darkseid, and the subsequent formation of the titular superhero team to counter it, which includes Superman, Batman, Wonder Woman, Flash, Green Lantern, Cyborg and Shazam. A stand-alone sequel, Justice League: Throne of Atlantis, was released in January 2015. The film also begins a story-arc which is revisited in Reign of the Supermen and concludes in Justice League Dark: Apokolips War.

The Justice League, or Justice League of America (JLA), is a group of superheroes appearing in American comic books published by DC Comics. The team first appeared in The Brave and the Bold #28. The team was conceived by writer Gardner Fox as a revival of the Justice Society of America, a similar team from DC Comics from the 1940s which had been pulled out of print due to a decline in sales.