A group of Police Academy graduates are sent to train a group of newly recruited civilian officers. The original Police Academy cast reprise their roles in the film. Capt. Harris, not seen since the first installment, returns as the film's nemesis. In Police Academy 2 and 3, Capt. Mauser (played by Art Metrano) filled that role, but Metrano asked to be replaced for the remainder of the series after filming number 3. This was the last Police Academy movie to feature Steve Guttenberg as Carey Mahoney. This film also stars a young David Spade, as well as a brief appearance from pro skateboarder Tony Hawk as Spade's double in a skateboarding scene.
Commandant Eric Lassard (George Gaynes) decides that the police force is overworked and understaffed, so he comes up with the idea of recruiting civilian volunteers to work side-by-side with his officers in a program called "Citizens On Patrol" (COP). Carey Mahoney (Steve Guttenberg) and his friends Moses Hightower (Bubba Smith), Larvell Jones (Michael Winslow), Eugene Tackleberry (David Graf), Zed (Bobcat Goldthwait), Sweetchuck (Tim Kazurinsky), Laverne Hooks (Marion Ramsey), and Debbie Callahan (Leslie Easterbrook) are in charge of training the civilians. The civilians include the enormous Tommy "House" Conklin (Tab Thacker), gung-ho senior citizen Lois Feldman (Billie Bird), Tackleberry's own father-in-law, and skateboarding delinquents Kyle (David Spade) and Arnie (Brian Backer). They were caught by Capt. Harris and the judge is about to throw the book at them, until Mahoney speaks to the judge to let Arnie and Kyle join the COP program as alternative punishment. The judge agrees to this, and the boys are joined by their unsuccessful attorney, Butterworth (Derek McGrath).
Captain Thaddeus Harris (G. W. Bailey) believes "the concept of citizens doing police work is asinine" and is determined to see the COP program fail and take over Lassard's job at the academy. When Lassard leaves on an overseas conference, Harris, along with his right-hand man Lt. Proctor (Lance Kinsey), are put in charge of the academy and Harris immediately plots to make the COP volunteers quit and leave the police work to the officers. The volunteers however do well in their training. Mrs. Feldman excels in firing Tackleberry's .44 Magnum and the two find a friendly bond in each other. In training for water safety and drowning victim rescue, Zed "rescues" a cadet but experiences a personal loss of his no longer functioning Mickey Mouse watch, saying it was the last thing he ever stole before joining the academy. Through his loss Zed gains a love interest, Laura (Corinne Bohrer), a reporter/photographer who has come to the academy to view Lassard's COP program and takes a fancy to Zed. Unfortunately Harris ruins the moment and insults Zed and Laura, which causes Zed to replace Harris' deodorant with mace. In the next scene, while Zed instructs the volunteers on the very important matter of how to correctly eat a donut, Harris is seen wearing a medical device suspending his arms in the air. Despite the pranks played upon him during the various training exercises the volunteers take, Harris is determined to make the Citizens on Patrol program fail.
Jones learns that volunteers House, Kyle, and Arnie believe themselves ready to go out and catch criminals, so Jones, Mahoney, Hightower, and Tackleberry play a prank on the boys, locking the boys in a prisoner transport van with Hightower, who is posing as a Voodoo practitioner who reanimates his "dead" brother, played by Tackleberry, as a Jason Voorhees-esque maniac with a chainsaw to make them take their training more seriously. Later, after being yelled at again by Captain Harris and being called a disgrace, Zed is comforted again by Laura, who says she thinks he is perfect.
After several volunteers accidentally foil an undercover police sting, the Citizens on Patrol program is suspended, much to Harris' delight. While Harris gives a tour of his precinct, Proctor messes up and is tricked into releasing every inmate at the precinct 19 jail, including a team of ninjas, and special guest Randall "Tex" Cobb. After the criminals imprison Harris and his guests, they make their escape from the precinct only to run into Mrs. Feldman, who wastes no time informing the Lassard academy.
When Lassard's officers hear of the jailbreak, the COP volunteers are dispatched along with the regular officers to catch the escaped felons. After stopping a robbery and a high-speed air balloon chase, the felons are all recaptured. Meanwhile, House, Kyle, Arnie, and Butterworth save Harris and Proctor from drowning in a river after the latters' attempt (and fail) to participate in the chase, and Zed impresses his girlfriend Laura by saving Sweetchuck's life after they both fall out of a plane in mid-air. Several of the police chiefs who had gone to witness Lassard's program in action congratulate and compliment Lassard on his program and his officers.Steve Guttenberg as Sgt. Carey Mahoney
Bubba Smith as Sgt. Moses Hightower
Michael Winslow as Sgt. Larvell Jones
David Graf as Sgt. Eugene Tackleberry
Tim Kazurinsky as Officer Sweetchuck
Leslie Easterbrook as Lt. Debbie Callahan
Marion Ramsey as Sgt. Laverne Hooks
Brian Tochi as Officer Tomoko "Elvis" Nogata
Lance Kinsey as Lt. Proctor
G.W. Bailey as Capt. Thaddeus Harris
George Gaynes as Cmndt. Eric Lassard
George R. Robertson as Commissioner Henry Hurst
Bobcat Goldthwait as Officer Zed
Colleen Camp as Sgt./Lt. Kathleen Kirkland-Tackleberry
Derek McGrath as Butterworth
Scott Thomson as Sgt. Chad Copeland
Billie Bird as Mrs. Lois Feldman
David Spade as Kyle Ault
Brian Backer as Arnie
Tab Thacker as Tommy "House" Conklin
Corinne Bohrer as Laura
Sharon Stone as Claire Mattson
Cameo appearances by skateboarders Steve Caballero, Chris Miller, Tommy Guerrero, Lance Mountain, Mike McGill, Tony Hawk.
The film was universally panned by critics, with a 0% "Rotten" rating and an average reviewer rating of 2.4 out of 10 on Rotten Tomatoes. The film was nominated for a Golden Raspberry Award for Worst Original Song for the song "Let's Go to Heaven in My Car". (It was the only film in the entire Police Academy film series to receive a Razzie nomination of any sort).
The film debuted at number one in the United States weekend box office and would go on to gross a total of $28,061,343. It ranks at number 44 of the year's top box office films. It faced stiff competition in United States theaters in early 1987 from such high-profile comedy releases as Beverly Hills Cop II, The Secret of My Success, The Witches of Eastwick, Dragnet, Outrageous Fortune, Mannequin, Roxanne, Blind Date, Spaceballs, Adventures in Babysitting, Revenge of the Nerds II: Nerds in Paradise, Harry and the Hendersons, Innerspace, Tin Men and Ernest Goes to Camp.
Motown Records issued a soundtrack album on record and cassette; until 2013, this was the only film of the series to have a soundtrack album released.
- Rock the House - Darryl Duncan (5:29)
- It's Time to Move - S.O.S. Band (3:19)
- Dancin' Up a Storm - Stacy Lattisaw (3:29)
- Let's Go to Heaven in My Car - Brian Wilson (3:30)
- The High Flyers (Police Academy Theme - Montage) - Robert Folk (2:04)
- Citizens on Patrol - Michael Winslow And The L.A. Dream Team (4:16)
- Rescue Me - Family Dream (4:54)
- I Like My Body - Chico DeBarge (3:56)
- Winning Streak - Garry Glenn (3:12)
- Shoot for the Top - Southern Pacific (2:46)