Critical response
Up received critical acclaim. On the review aggregator website Rotten Tomatoes, 98% of 291 critics' reviews are positive, with an average rating of 9.1/10. The website's consensus reads: "An exciting, funny, and poignant adventure, Up offers an impeccably crafted story told with wit and arranged with depth, as well as yet another visual Pixar treat." Metacritic (which uses a weighted average) assigned Up a score of 88 out of 100 based on 37 critics, indicating "universal acclaim". Audiences polled by CinemaScore gave the film a rare grade of "A+" on an A+ to F scale.
In a four-star (out of four) review, film critic Roger Ebert called it "a wonderful film", and "another masterwork from Pixar". The Hollywood Reporter lauded the film as "Winsome, touching and arguably the funniest Pixar effort ever, this gorgeously rendered, high-flying adventure is a tidy 90-minute distillation of all the signature touches that came before it." Although the San Francisco Chronicle noted that the film "contains many boring stretches of mindless freneticism and bland character interaction," it also declared that there are scenes in Up of "such beauty, economy and poetic wisdom that they belong in any anthology of great movie moments ... to watch Up with any attention is to be moved and astonished by the economy with which specific visuals are invested with emotion throughout [the film]." Variety enthused that "Up is an exceptionally refined picture; unlike so many animated films, it's not all about sensory bombardment and volume ... Unsurprisingly, no one puts a foot wrong here. Vocal performances ... exude a warm enthusiasm, and tech specifications could not be better. Michael Giacchino's full-bodied, traditional score is superlative". The Globe and Mail stated that Up is "the kind of movie that leaves you asking 'How do people come up with this stuff?'" along with an overall positive review of the film, despite it being predictable.
The character of Carl Fredricksen has received mostly positive reception. Bill Capodagli, author of Innovate the Pixar Way, praised Carl for his ability to be a jerk and likable at the same time. Wall Street Journal editor Joe Morgenstern described Carl as gruff, comparing him to Buster Keaton, but adds that this begins to wear thin as the movie progresses. He has been compared with Spencer Tracy, an influence on the character, by The Washington Post editor Ann Hornaday and Empire editor Ian Freer, who describes him as similar to a "Guess Who's Coming to Dinner-era" Tracy. Entertainment Weekly editor Lisa Schwarzbaum described his appearance as a cross between Tracy and an eccentric out of a George Booth cartoon. Time editor Richard Corliss also makes the comparison, calling him a "trash compacted version" of Tracy. He has also been compared to Walter Matthau, another inspiration for the character's design, by LA Weekly editor Scott Foundas, suggesting that actor Ed Asner was channeling him while performing the role of Carl. Variety editor Todd McCarthy described Carl as a combination of both Tracy and Matthau.
The relationship between Carl and his wife Ellie has been praised in several media outlets. In his book Disney, Pixar, and the Hidden Message of Children's Films, author M. Keith Booker described the love between Carl and Ellie as touching. While also describing the scene of the two of them aging as a "masterpiece of its own kind", he was not sure how much children would appreciate the scene, commenting that his son was squirming in his seat during the scene. Reelviews editor James Berardinelli praised their relationship, stating that it brought a tear to his eye in a way no animated film has done, including anything by famed anime director Hayao Miyazaki. Ann Hornaday praised the prologue, describing it as "worthy of Chaplin in its heartbreaking poignancy." Chicago Tribune editor Michael Phillips praised the scene, describing it as an emotional and cinematic powerhouse, and that he also was nearly moved to tears. However, Salon editor Stephanie Zacharek criticized the love between Carl and Ellie, describing their marriage as resembling a dental adhesive commercial more than a real relationship.
Asner was praised in several media outlets for his portrayal of Carl. San Francisco Chronicle editor Mick LaSalle praised Asner as a great choice due to having a grumpiness to his voice that is not truly grumpy, but rather coming from a protective stance. Entertainment Weekly editor Lisa Schwarzbaum praised Asner's acting, stating that he has a "Lou Grant authority" to his voice. Time editor Richard Corliss stated that Asner had the "gruffness and deadpan comic timing to bring Carl to life." The Boston Globe editor Ty Burr concurred with this, stating that his Lou Grant-like voice had not diminished with time. USA Today editor Claudia Puig praised Asner's delivery, describing it as superb.
The formulation of Russell as an Asian-American character, along with the casting of an Asian-American in the role was met positively as well. Both Nagai and the film were awarded by the East West Players for the depiction of Russell. EWP lauded Pixar for the creation of the character, stating, "We are proud to honor a very progressive film company like Pixar who cast an Asian-American character alongside an elderly one to play the leads in a feature film." The character is noted as Pixar's first lead Asian character, and was further positively received within the added context of historical non-Asian castings for Asian roles in entertainment. Asian-American organizations and entertainment websites, such as media watchdog Media Action Network for Asian Americans (MANAA), Racebending.com, and Angry Asian Man praised the character and Pixar for its diverse character depictions, noting the general lack of Asian-American lead characters and Asian actors cast in entertainment. In an interview with NPR in 2013, Angry Asian Man's Phil Yu reflected on the character's lack of typical Asian stereotyping, stating, "You know, he just happens to be Asian and he's, you know, really adorable character. But that kid could've been of any ethnicity but they made the effort to make him Asian—just a little color, you know, and it's really wonderful when that kind of thing happens where they don't have to play that up and make it like a thing or a joke, which happens a lot."
Up was included on a number of best-of lists. It appeared on professional rankings from Empire based on retrospective appraisal, as one of the greatest films of the twenty-first century. Several publications have listed it as one of the best animated films, including: Entertainment Weekly (2009), IGN (2010), Time (2011), Insider, USA Today (both 2018), Rolling Stone (2019), Esquire (2020), Parade, Time Out New York, and Empire (all 2021). In December 2021, the film's screenplay was listed number thirty-three on the Writers Guild of America's "101 Greatest Screenplays of the 21st Century (So Far)". The February 2020 issue of New York Magazine lists Up as among "The Best Movies That Lost Best Picture at the Oscars." In 2025, the film ranked number 50 on The New York Times' list of "The 100 Best Movies of the 21st Century" and number 85 on the "Readers' Choice" edition of the list.
