The film follows Zu, a newly sober drug dealer who becomes the sole guardian of her half-sister Music, a teenage non-verbal autistic girl.

Zu learns how to take care of Music with Ebo's help but continues to deal drugs to fund her dream to move to Costa Rica.

Zu cannot afford the treatment and realizes that she has left her bag in the park, which contained drugs intended to be sold to a pop star.

[11] The film's screenplay was co-written by Sia and children's book author Dallas Clayton based on a one-page story that she had written in 2007.

[35] A clip of Hudson singing the song "1+1" exclusively aired on the MTV Movie and TV Awards: Greatest of All Time on December 6, 2020.

The website's critics consensus reads, "Offensive in its depiction of autism—and painfully misguided in essentially every respect—Music is a vanity project that begs to be turned down.

"[62] According to Metacritic, which assigned the film a weighted average score of 23 out of 100 based on 18 critics, Music received "generally unfavorable reviews".

[64] Jake Wilson of The Sydney Morning Herald called the film "scarcely less of a baffling fiasco" than Tom Hooper's Cats, that "leaves you wondering what anyone was thinking" and said the casting of Ziegler as an autistic girl is "self-evidently problematic" in the 2020s.

[65] James Croot of Stuff also compared Music to Cats, and wrote that the "characters are one-dimensional" and that "an inexplicable cameo from Sia herself is simply bizarre".

[1] Stephen Russell of Time Out stated that Music is "a well-intentioned but messily fantastical neurodiversity drama", giving it 2 out of 5 stars and comparing it to Rain Man.

[66] Charlotte O'Sullivan, writing for the Evening Standard, gave the same rating and criticised the film, describing it as a "crass and lazy mess".

[68] Johnny Oleksinski, writing for the New York Post, called the film "unwatchable and offensive", giving it 0 out of 5 stars, saying that "Sia should leave the director's chair behind".

[69] Teo Bugbee of The New York Times called Music a "cringeworthy drama", saying that the film "reduces disability to mannerisms that look indistinguishable from mockery.

"[70] Lucy Rutherford of PerthNow accused the film of being "tone deaf", and wrote that the narrative flow being "interrupted by an album's worth of Sia music videos gets old very quickly".

[71] Tim Robey of The Daily Telegraph also gave the film 2 out of 5 stars, describing it as a "poorly judged, [...] fitfully peppy mess".

[74] Writing for Slate, Sara Luterman said that she felt "acute discomfort of watching [Ziegler] clumsily ape disability" and comments that "despite the movie's eponymous title", Music is more about Zu than the titular character.

[75] Multiple reviews noted parallels between Music and the 2008 film Tropic Thunder starring Ben Stiller as, in Matthew Rozsa of Salon's words, "an actor who tries to win an Oscar by playing a mentally disabled person and fails because his performance is so over-the-top way that it becomes cringe-y rather than compelling.

"[76][77] Luke Buckmaster of The Guardian gave the film 2 out of 5 stars and wrote it "lacks credibility", with Ziegler's "distracting" performance feeling "ill-judged at best".

[78] Clem Bastow, writing for the same publication, criticized Music's portrayal of autism, stating that it used "abject stereotypes", and noting that Ziegler's performance as the title character is the "standout disaster, serving us 'autism' the Rain Man way."

"[81] Matt Zoller Seitz for Roger Ebert.com wrote that "the film seems to be going for a gritty-yet-also-magical-and-empowering vibe" which lacked common sense and felt insincere and hollow even with its artistry and compassion.

[83] Mark Morellini of Star Observer wrote that the film is "a joy to watch", and also applauded Ziegler's performance, describing it as "realistic and emotionally charged".

[97] Helen Brown of The Independent argued that the film's depiction of the restraint could be dangerous, as neurotypical people may come away thinking it is acceptable to "crush" an autistic person when they are having a meltdown.

[98] Hudson, while appearing on Jimmy Kimmel Live!, commented that she believes the depiction of autism "is an important conversation to have – not just about [Music], but as a whole about representation".

[99] Sia stated that, prior to the film's release, the Child Mind Institute had given Ziegler's portrayal of an autistic character a 100 percent approval rating.

[101] Danish autism advocate Nina Skov Jensen started a Change.org petition calling for the film's Golden Globe nominations to be rescinded, which had received over 140,000 signatures as of March 16, 2021.