The returning voices of Owen Wilson, Larry the Cable Guy, Bonnie Hunt, Tony Shalhoub, Guido Quaroni, Cheech Marin, Jenifer Lewis, Paul Dooley, Lloyd Sherr, Michael Wallis, Katherine Helmond and John Ratzenberger are joined by Cristela Alonzo, Chris Cooper, Armie Hammer, Nathan Fillion, Kerry Washington, and Lea DeLaria, in addition to a dozen NASCAR personalities.

In the film, Lightning McQueen (Wilson), now a veteran race car, must prove that he is still competitive against a new generation of technologically advanced racers, with the help of young technician Cruz Ramirez (Alonzo), to prevent a forced retirement from the Piston Cup.

The production team for the film conducted research on multiple NASCAR racers, particularly older ones, as well as a sports psychoanalyst, while also focusing on McQueen's relationship with Doc Hudson and its meaning.

Cars 3 was first screened for the NASCAR industry in Kannapolis, North Carolina on May 23, 2017, before its theatrical release in the United States on June 16, accompanied by the animated short film Lou.

Five years after competing in the World Grand Prix,[b] Lightning McQueen, now a seven-time Piston Cup champion,[5] finds himself overshadowed by Jackson Storm, a rookie who is the first of a new generation of race cars that are equipped with advanced technology to improve their speed and performance.

In the final race of the season at Los Angeles, Lightning briefly gains first place but starts falling behind after being overtaken by Storm and the other next-gen racers.

He desperately tries to keep up, but in doing so, loses control and suffers a rollover crash after hitting the outside wall, leaving him unable to race and ending his worst season on record prematurely.

Four months later, Lightning, who has since recovered from his crash, decides that he will continue racing and calls his sponsors, Rusty and Dusty, who reveal they have sold Rust-eze to a wealthy business car named Sterling.

Cruz's unconventional training methods and lack of real-world racing experience frustrate Lightning as they attempt to record his top speed at Fireball Beach.

When Lightning decides to train at the Thunder Hollow Speedway, they realize it is being used for a figure-8 style demolition derby called the "Crazy Eight" and are forced to participate, in which Cruz wins and accidentally reveals him to the public.

[c] After Lightning accepts that he is an older car and will never be as fast as Storm, Smokey and Doc's old friends, Louise "Barnstormer" Nash, River Scott, and Junior "Midnight" Moon, help him learn new tricks to overcome his speed disadvantage, using Cruz as his sparring partner.

Sterling, who still believes that Lightning cannot win, orders Cruz back to the training center to prepare a rookie for the following race despite her wanting to stay.

Additionally, several NASCAR drivers and other related personalities made cameo appearances, including Chase Elliott as Chase Racelott, Ryan Blaney as Ryan "Inside" Laney, Bubba Wallace as Bubba Wheelhouse, Shannon Spake as Shannon Spokes, Daniel Suárez as Danny Swervez, Ray Evernham as Ray Reverham, and Mike Joy as Mike Joyride.

[8] The production utilized a new rendering mode, Rix Integration Subsystem (RIS), which made scenes like the demolition derby race possible.

Director of photography-camera Jeremy Lasky and editor Jason Hudak researched NASCAR footage for the film's race scenes.

Physical copies contain an audio commentary, behind-the-scenes featurettes, deleted scenes, and the short films Miss Fritter's Racing Skoool and Lou.

[33] The BBC, Disney and Lego released a short film via YouTube, on April 13, 2018, that is inspired by both the Cars franchise as well as the popular TV series Top Gear.

The film tells the story of Lightning McQueen's trip to the Top Gear track, where he achieves his dream of racing against the Stig.

[4] In North America, Cars 3 was released alongside Rough Night, 47 Meters Down and All Eyez on Me, and was projected to gross $55–60 million from 4,256 theaters in its opening weekend.

The website's consensus reads: "Cars 3 has an unexpectedly poignant story to go with its dazzling animation, suggesting Pixar's most middle-of-the-road franchise may have a surprising amount of tread left.

[43] Owen Gleiberman of Variety wrote, "Cars 3 is a friendly, rollicking movie made with warmth and dash, and to the extent that it taps our primal affection for this series, it more than gets the job done.

"[46] Alonso Duralde of TheWrap gave the film a mixed review, saying: "As a spawner of merchandise, Cars 3 fires on all pistons but, as a movie, it's a harmless but never stimulating 109 minutes.

[64] In December 2023, during an interview at the 2023 Porsche Rennsport Reunion Event, the creative director of the saga, Jay Ward, revealed that Pixar is developing new projects related to the franchise: "There are more Cars things brewing, I can't say much more yet.