Zack Snyder's Justice League

Tom Holkenborg, also known as Junkie XL, composed the film's score; he had previously completed an entire score for the theatrical version of Justice League, before being replaced by Danny Elfman following Snyder's departure and Whedon's arrival. When Holkenborg was rehired to score the film in early 2020, he decided to restart and make a brand new score for the film, which consists of fifty-four tracks and is three hours and 54 minutes long.

The first track from the score, "The Crew at Warpower", was released on February 17, 2021. Holkenborg has described this score as a "national anthem" for Snyder's Justice League and has confirmed this plays during the 10 minute intermission halfway through theatrical screenings of the movie. A second track, "Middle Mass", was released on March 12, 2021. Holkenborg described the score as "fully electronic [at times], and at other times fully orchestral", incorporating elements of rock and trap. The album was released via WaterTower Music on March 18, 2021, the same day as the film's release.

The beginning of the movie features a traditional Icelandic song "Vísur Vatnsenda-Rósu", not included in the original motion picture soundtrack.

Allison Crowe's cover of the Leonard Cohen song "Hallelujah" plays during the end credits as a tribute to Autumn Snyder.