Nine years after getting married,^[a] Jim Levenstein and his wife Michelle are in a sexual rut following the birth of their 2-year-old son. Kevin Myers is a househusband and architect, Chris "Oz" Ostreicher is a celebrity sportscaster dating Mia, a superficial supermodel, and Paul Finch has been traveling the world. The four friends return from their disparate locations to East Great Falls, Michigan, for their thirteen-year high school reunion. They are unintentionally joined by Steven Stifler, whom they hoped to avoid. Jim encounters Kara, a former neighbor who he used to babysit. She invites him to her 18th birthday party and he reluctantly accepts.

The guys spend the following day at the lake with Michelle and her friend Selena, whom Finch bonds with. Kevin and Oz reunite with their high school girlfriends Vicky and Heather, and meet Heather's boyfriend, Ron. Kara's boyfriend AJ steals bikini tops from Mia and other women before fleeing on a jet ski. The guys track AJ and his friends to a nearby beach where Jim overhears AJ's boastful plans to take Kara's virginity. Stifler destroys their jet skis and the guys flee.

Instead of spending time with Michelle, Jim accompanies the others to the falls where they find Kara's party. Unsatisfied with Heather, Ron suggests swapping girlfriends to a disgusted Oz. Kara drunkenly tries to seduce Jim, but he rejects her. When she passes out, Jim recruits Stifler, Finch, and Oz to distract her parents while he sneaks her into her bedroom. Jim returns home and falls asleep, further leaving Michelle despondent about their marriage. The following morning, Kevin wakes up in bed with Vicky and assumes they had drunken sex. She confirms they did not but is upset he thinks so lowly of her.

Jim encourages his widower dad Noah to begin dating, so they bring him to Stifler's house party where he meets Stifler's mother, Jeanine. Oz admits his continued feelings for Heather; Mia finds out and breaks up with him. Jim waits upstairs for Michelle so they can have sex, but Kara again tries to seduce him. AJ intervenes and a fight ensues. Jim explains the situation to Michelle and states he does not care about Kara, causing both women to leave upset. The police arrive and arrest Finch for stealing a motorbike. Stifler mocks Finch, and the guys confront him over being a bad friend and his inability to move on from high school. Stifler reminds them that they have ignored and avoided him for years.

The next day, Noah offers Jim advice on repairing his marriage. At the reunion, Finch admits that he lied about his travels because he was embarrassed to admit that he has a normal job as a retailer manager and stole the bike from his neglectful boss. Feeling guilty about their treatment of Stifler, the guys visit him at work and apologize, solidifying their friendship. Stifler confronts his verbally abusive boss and quits.

The guys returns to the reunion together where Kevin reconciles with Vicky, Finch makes amends to Selena, Oz and Heather choose to be together, and Jim and Michelle finally have sex. Stifler is offered work as a wedding planner and is seduced by Finch's mother, Rachel.

The guys meet up the following day: Oz reveals he is staying in town with Heather; Finch intends to tour Europe with Selena; and Jim apologizes to Kara, who plans to save her virginity for a good man like him. Kevin proposes a pact for the group to meet up every year from now on. Stifler teases Finch about his mom.

In October 2008, Universal Pictures announced it was planning to produce a fourth theatrically released sequel to the first film.^[5] In April 2010, the film entered pre-production, with Jon Hurwitz and Hayden Schlossberg signing on to write and direct with plans to reunite the whole cast of the primary series.^[6]

In March 2011, it was announced that Jason Biggs, Seann William Scott and Eugene Levy had signed on to reprise their roles.^[7] Biggs and Scott were granted executive producer credits and also helped convince the other previous cast members to return.^[8] In April 2011, Alyson Hannigan, Chris Klein, and Mena Suvari signed on.^[9][10][11] The following month, Thomas Ian Nicholas, Tara Reid, Eddie Kaye Thomas,^[12] Shannon Elizabeth,^[13] and Jennifer Coolidge^[14] signed on. In June and July 2011, John Cho^[15] and Natasha Lyonne^[16] were the last returning cast to sign on.

On May 18, 2011, a casting call went out for the character "Kara", a role that involved "upper frontal nudity".^[17] Ali Cobrin was cast in the role. National Football League wide receiver Chad Ochocinco and actor Neil Patrick Harris have cameo roles.^[18][19]

Jason Biggs and Seann William Scott each received a reported $5 million plus a percentage of the profits for their performances. Alyson Hannigan and Eugene Levy were said to have been paid $3 million each, with the rest of the cast receiving payments within the $500,000 to $700,000 range, except Tara Reid, who was paid $250,000.^[20]

On a budget of $50 million,^[21] principal photography took place from early June to August 2011 in metro Atlanta, Georgia.^[13][22] In late June, filming took place at Conyers, Monroe and Woodruff Park.^[19][23] While in Conyers, filming took place at Heritage High School’s football stadium and band room. Production filmed at Newton High School in Covington from July 11 to July 15. Scenes were filmed at the school's gym for a reunion prom set, football field, commons area and hallways; which included 200 extras. Under the deal the production company paid $10,000 to the Newton County School System for using the school.^[23]

During the last week of July, production moved to Cumming to film at Mary Alice Park on Lake Lanier and included about 100 extras.^[24] Moore said the beach at the lake looks similar to a Lake Michigan setting, which is the state in which the film is set. The production company paid $23,000 to have full access to the property for a week.^[24] Suvari finished filming her scenes on August 4.^[25]

Professional ratings

Review scores
Source	Rating
AllMusic	[26]

The two score tracks were recorded by a 60-70 piece orchestra conducted by John Ashton Thomas who also orchestrated Workman's score for the orchestral sessions. The orchestra was recorded at the Eastwood Scoring Stage at the Warner Bros. lot by Shawn Murphy who also mixed the score.

American Reunion was released in North American theaters on April 6, 2012.

The DVD and Blu-ray discs were released on July 10, 2012 in North America.^[27] The film was also released in a box set titled the "American Pie Quadrilogy" on August 22, 2012, in Australia. The theatrical version was available on iTunes a few days ahead of time, as an "Early Digital Release". It was released on September 10, 2012, in the United Kingdom.^{[citation needed]}

American Reunion opened in North America on April 6, 2012, in 3,192 theaters for a weekend total of $21,514,080, putting it at number 2 at the box office behind The Hunger Games.^[28] On its second week of release, it dropped to number 5 at the box office with a weekend total of $10,473,810.^[29]

The film earned $56,758,835 in North America and $177,978,063 internationally, for a worldwide total of $234,736,898.^[2]

On Rotten Tomatoes, the film holds an approval rating of 45% based on 186 reviews, with an average rating of 5.3/10. The site's critical consensus reads, "It'll provide sweetly nostalgic comfort food for fans of the franchise, but American Reunion fails to do anything truly new or interesting – or even very funny – with the characters."^[30] On Metacritic, the film has a weighted average score of 49 out of 100, based on 34 critics, indicating "mixed or average" reviews.^[31] Audiences polled by CinemaScore gave the film an average grade of "B+" on an A+ to F scale.^[32]

According to Roger Ebert, who gave the film three out of four stars:^[33]

The charm of American Pie was the relative youth and naïveté of the characters. It was all happening for the first time, and they had the single-minded obsession with sex typical of many teenagers. American Reunion has a sense of déjà-vu, but it still delivers a lot of nice laughs. Most of them for me came thanks to Stifler... If you liked the earlier films, I suppose you gotta see this one. Otherwise, I dunno.

The Village Voice concludes its review with the following:^[34]

After some strained "Remember the time..." callbacks to 13-year-old gags, American Reunion gets comfortable and funny, as Hurwitz and Schlossberg hit familiar marks from unexpected angles, while the ensemble interplay is "routine" in the best sense of the word. Taken altogether, the Pie movies offer a cohesive worldview, showing each of life's stages as the setting for fresh-yet-familiar catastrophes, relieved by a belief in sex, however ridiculous it might look, as a restorative force. The recipe is so durable and the sustained character work so second-skin by now, one can imagine the Pie films keeping with the dramatis personae through middle age and into the problems of geriatric love, a raunch-comic version of Britain's documentary Up series. American Midlife Crisis? American Retirement? American Funeral? Let's go!

Peter Travers of Rolling Stone gave American Reunion a positive review of two and half stars out of four saying, "American Reunion reminds us what we liked about the original: the way the movie sweetened its raunch to build a rooting interest in these characters."^[35]

In August 2017, Seann William Scott said in an interview that the fourth film probably had not made enough at the domestic box office to warrant another film.^[37] In August 2018, Tara Reid said she met with the directors, with them saying that the fifth film will happen, and that filming could begin soon.^[38] In September 2022, it was announced that Universal 1440 was developing another spin off American Pie Presents movie with Sujata Day.^[39]