Batman: The Long Halloween is a 2021 American two-part animated direct-to-video superhero film produced by Warner Bros. Animation and DC Entertainment, based on the DC Comics storyline of the same name. Part 1 is the 44th film, and Part 2 is the 45th film, of the DC Universe Animated Original Movies, with both parts serving as the third and fourth installments of the Tomorrowverse. The film is directed by Chris Palmer and stars the voices of Jensen Ackles, Naya Rivera, Josh Duhamel, Billy Burke, Titus Welliver, David Dastmalchian, Troy Baker, Amy Landecker, Julie Nathanson, Jack Quaid, Fred Tatasciore and Alastair Duncan. The film is dedicated to Rivera, as it was her final film role before her death in 2020. In both parts of the film, Batman attempts to unravel the mystery of murders committed on holidays throughout the year, and uncover the true identity of the serial killer Holiday.

Part 1 was released on June 27, 2021, and Part 2 was released on July 27 the same year. A deluxe edition combining both films was released on September 20, 2022.