In a world populated by anthropomorphic mammals, Judy Hopps from rural Bunnyburrow dreams of becoming a police officer, expressing it through a slightly comical skit at a country fair. Later, she sees one of her friends bullied by a fox named Gideon Grey. Afterwards, she steps in, and sneakily retrieves her friends’ tickets, further encouraging her to fulfill her childhood dream of becoming a police officer in urban Zootopia. Despite being the academy valedictorian, Judy is delegated to parking duty by Chief Bogo, who doubts her potential because she is a rabbit. On her first day, she gets 200 tickets put on cars before noon. Later, she sees a fox entering an ice cream shop, then being refused because he is a fox. Judy steps in and slyly threatens the owner of the store if he doesn’t sell the fox and his little baby boy a Jumbo-pop. Outside, the fox introduces himself as Nick Wilde, then thanking her for her kindness. Judy also gives the “baby” a sticker of a police badge. Later, while she puts a ticket on a buggy, she sees that Nick and the “baby” were melting down the Jumbo-pop and reselling it as smaller “pawpsicles,” then labelling the used sticks as “redwood” and selling them. Judy tries to arrest Nick for false advertising, selling without permit, as well as a Proceed of Declared Commerce. The argument goes on, with Nick dodging the questions effortlessly, much to Judy’s annoyance. She becomes so annoyed in fact that she unknowingly walks backwards into wet cement.
The next day, a depressed Judy is called on by a florist to catch a crook who stole his flowers. She gladly abandons parking duty to arrest Duke Weaselton, a weasel who stole a bag of crocus bulbs known as Midnicampum holicithias, as well as saving an arctic shrew named Fru Fru from a giant donut that was toppled over in the chase. Bogo reprimands her, but Mrs. Otterton enters Bogo’s office pleading for someone to find her husband Emmitt, one of fourteen predators who are missing. When Judy volunteers and Assistant Mayor Dawn Bellwether praises the assignment, Bogo grudgingly gives her 48 hours to find Otterton on the condition that she resigns if she fails. Judy thinks at first, but later accepts.
In the case file, she sees a picture of the last known sighting of Emmitt Otterton, licking a popsicle. She uses an empty drinks bottle to magnify it, revealing that it was a “pawpsicle,” leading her to the conclusion that Nick was at the scene. After determining Nick was a suspect seen in Otterton’s last known sighting, Judy intercepts Nick, asking him for his help. After Nick refuses, Judy cunningly blackmails him into assisting her by covertly recording his confession to tax evasion with her carrot pen. They track Otterton down to his yoga place, Mystic Springs Oasis, where they find that Otterton went in a limousine that had the license plate 29THD03. They track the limo to a car owned by Tundratown Limo Service. After Nick finds out she doesn’t have a warrant, Judy “admits” this and “gives” Nick the pen. But as Nick tries to get it, she throws it over the fence, prompting Nick to climb the fence. But he was too late, as Judy already made it, and told him that she didn’t need a warrant if she had a probable cause, which was that a shifty lowlife (Nick) trespassed by climbing the fence. The investigation continues, and once they are in the limo, Nick suddenly realizes that the limo belongs to the biggest crime boss in Tundratown, Mr. Big, who doesn’t like Nick at all. But before he can explain, they are caught by two of Mr. Big’s henchmen. In the car, Nick explains that he pissed off Mr. Big by selling him a rug made from a skunk’s rear end. After nearly being killed by Mr. Big, Fru Fru angrily objects, saying that Judy saved her life the day before. After this, Mr. Big repents and invites them to his daughter’s wedding. During dinner, Mr. Big reveals that Otterton went “savage” – reverted to a feral state – and attacked his chauffeur Manchas. At his home, Manchas mentions Otterton kept yelling about the “night howlers” before the attack. Moments later, Manchas himself turns savage and chases the pair. Judy saves Nick by trapping Manchas with the cuff and calls the ZPD for help, but when they arrive, Manchas has vanished. Bogo demands Judy’s resignation, but Nick barges in, exposing Bogo’s abject refusal to help them, also reminding Bogo that Judy still has ten hours to solve the case. Judy learns from Nick that he was bullied as a child when he tried to join the Ranger Scouts, who stereotyped him as untrustworthy for being a fox, leading him to dislike fox muzzles and taking on a sarcastic attitude.
At City Hall, Bellwether offers Judy and Nick access to the city’s traffic cameras. They discover Manchas was captured by wolves, who Judy surmises are the “night howlers”. They locate the missing predators – all gone savage – imprisoned at Cliffside Asylum, where Mayor Leodore Lionheart hides them from the public while scientists try to determine the cause of their behavior. Judy and Nick video the entire conversation, but her phone rings, giving the game away. They escape by flushing themselves out. Lionheart and those involved are arrested for false imprisonment and Bellwether becomes the new mayor.
Judy, praised for solving the case, has become friends with Nick and asks him to join the ZPD as her partner. Nick accepts, and stands on the sidelines as Judy handles the press conference. However, she upsets him at a point in the press conference, by suggesting a predatory biological cause for the recent savage behavior due to a loss for words, and her comments cause tension between predators and prey throughout the city. Feeling guilty for the results of her words, Judy quits her job.
Back in Bunnyburrow, a depressed Judy witnesses Gideon Grey’s baking van pull up in front of the house. Suddenly, Judy’s dad, Stu, warns some of his children away from a patch of Midnicampum holicithias. Gideon Grey is surprised that Stu used the botanical name, saying that he prefers to just call them night howlers. Judy then realizes that the night howlers are actually toxic flowers that have severe psychotropic effects on mammals. After returning to Zootopia and reconciling with Nick, the pair confront Weaselton, who at first is adamant about coughing up information. Later though, after nearly getting iced by Mr. Big, he does eventually tell them that the bulbs he stole were for a ram named Doug. They find Doug in a laboratory hidden in the city subway, developing a drug made from night howlers, which he has been shooting at predators with a dart gun.
Judy and Nick obtain the serum as evidence, but before they can reach the ZPD, Bellwether confronts them and takes the evidence, indirectly revealing herself as the mastermind behind a prey-supremacist conspiracy. Judy and Nick are trapped in a massive diorama that is in a hole in the floor, after Nick refuses to abandon an injured Judy. Bellwether shoots a “serum” pellet at Nick to make him go savage and kill Judy, and summons the ZPD for help so that she could cover up the facts, but Judy and Nick had cleverly replaced the serum pellets in Bellwether’s gun with blueberries. Bellwether threatens to frame the pair for the attacks, but Judy has recorded Bellwether’s confession on the carrot pen recorder. Bogo and the ZPD arrive and Bellwether, as well as her hen grams, are arrested.
Lionheart publicly denies knowledge of Bellwether’s plot and states that his imprisonment of the savage predators was a “wrong thing for the right reason”. With the cause of the epidemic identified, the savage animals are cured and Judy rejoins the ZPD. Nick graduates from the Zootopia Police Academy as the city’s first fox police officer and becomes Judy’s partner. They kiddingly tease each other a little in the police car. At their green light, a car zooms past at 115 mph, but the driver is ironically Flash.