Fourteen-year-old Duncan from Albany, New York reluctantly goes on summer vacation to a beach house in a small seaside town near Cape Cod, Massachusetts with his mother, Pam; her wealthy boyfriend, Trent; and Trent's daughter, Steph. Trent emotionally belittles Duncan, frequently making comments and gestures that are condescending and rude to him, Steph sequentially, is equally rude and snooty toward him and is spoiled by Trent. On the way to the beach house, Trent asks Duncan to rate himself on a scale of one to ten; Duncan rates himself a six while Trent tells him he thinks Duncan is a three. They arrive at the beach house and are greeted by the neighbors: the gregarious, hard-drinking Betty; her children Susanna and Peter; and married couple Kip and Joan. Later that evening, Duncan and Susanna have an awkward conversation from their adjacent porches.
Duncan discovers a small girl's bicycle in the garage of the beach house and uses it to begin exploring the town. At a pizza restaurant, he runs into the staff of Water Wizz, the local water park. He meets Owen, who is playing Pac-Man, and eventually Owen takes Duncan under his wing and shows him around the park. Duncan meets the park's colorful, rag-tag group of employees: Caitlin, Lewis, and Roddy. Several kids at the water park speak reverently of a legendary pass in the tube slide, wondering how it could have been done. Owen hires Duncan for odd jobs at Water Wizz.
Outside the park, Duncan is continually neglected by his mother, Pam, who indulges in drinking, staying out at night, and smoking marijuana with other adult vacationers. At a Fourth of July cookout, Susanna sees that he is upset about this and invites him to go hunting for ghost crabs with her and Peter, where she talks about her absent father and helps Duncan to open up. Later that night, Duncan witnesses Trent and Joan kissing by the side of the house, but does not reveal what he saw.
Pam begins to suspect Trent and Joan are having an affair, but Trent convinces her nothing is going on. Later, Duncan confronts Pam in front of friends and neighbors and tells her to face up to Trent's affair and get rid of him. Trent in turn tells Duncan his divorced father does not want him. Duncan stalks away. Susanna follows him and comforts Duncan out on the beach. Duncan attempts to kiss Susanna, but she moves away, which makes him become even more upset. Accompanied by Peter, Duncan sneaks away to Water Wizz where Owen is throwing a going away party for Lewis.
After spending all night with his friends at Water Wizz, Duncan is still at the park the next morning, refusing to leave. Owen confronts him and asks him why he does not want to go home. Duncan opens up to Owen about his relationship with Trent and how the water park is the only place where he feels happy and accepted. Owen sympathizes with Duncan's problems.
When Duncan arrives back at the beach house, Pam tells him they are leaving with Trent and Steph. Betty and her kids arrive to say their goodbyes. Susanna finally kisses Duncan. When Trent stops for gas on their way out of town, Duncan jumps out of the station wagon and runs to Water Wizz, followed by his mother, then Trent and Steph. Duncan tells Owen and the other employees that he has to leave and tells Owen to follow him. He takes Owen to the Devil's Peak slide, and Duncan becomes the first person to ever pass someone in the water slide while the rest of the park watches. After finally introducing Owen to his mother, Duncan says goodbye to everyone at the park. Owen tells Pam she has a great kid, and introduces himself to Trent as "a good friend of the three". Trent, Steph, Pam and Duncan regroup in the car, where Pam finally stands up for herself as they head out of town. Pam climbs to the way, way back of the car where Duncan is sitting and they share a smile as Trent's protests are heard in the background.
The film had its premiere screening at the 2013 Sundance Film Festival. The film became one of the most financially successful films to come out of the festival that year, outperforming well-known entries and Oscar-nominated films from the previous year. It was released on July 5, 2013 in 19 theaters and surpassed box office expectations, averaging an impressive $30,263 per screen and grossed $525,000 total for the weekend. On July 15, 2013, the film was added to an additional 60 theaters, and grossed $1,110,000. The film ended up earning $21,506,546 in North America and $4,968,374 elsewhere for a total of $26,474,920.
The Way, Way Back received positive reviews and has a rating of 85% on Rotten Tomatoes based on 172 reviews with an average score of 7.3 out of 10. The consensus states, "Despite its familiar themes, The Way Way Back makes use of its talented cast, finely tuned script, and an abundance of charm to deliver a funny and satisfying coming-of-age story". The film also has a score of 68 out of 100 on Metacritic based on 41 reviews.
Inkoo Kang of The Village Voice called, The Way, Way Back "a crowd-pleasing summer treat, predictable in its sweetness but satisfying all the same". BBC Radio 5 Live film critic Mark Kermode praised the performances of Sam Rockwell, Toni Collette, Allison Janney and Maya Rudolph and similarly reasoned that whilst "it's not world-changing, or earth-shattering" the film is "really sweet and funny". David Gritten of The Telegraph also praised the scene-stealing performances of Janney and Rockwell, concluding that despite a flood of similar coming-of-age films released in 2013 the film "feels warm, funny—and even fresh". Catherine Shoard of The Guardian gave the film a positive review, concluding that "for all the longueurs, there are still enough moments of near brilliance to sustain you through the trip". Betsy Sharkey of the Los Angeles Times commended the film's quirky dialogue and cast performances, calling the film "witty, heartwarming, hopeful, sentimental, searing and relatable".
Sam Rockwell's performance was met with critical praise, with many critics agreeing that his performance was deserving of an Academy Award nomination. MaryAnn Johanson of Flick Filosopher said that Rockwell "makes the biggest splash with a sizzling supporting performance. Not only is he naturally funny, but he has the great ability to make every sharp line of dialogue sound freshly improvised."
By contrast The A.V. Club gave the film a C+, describing it as "generically constructed" and "never as refreshing as it’s constantly straining to be".
Heather Phares of Allmusic gave the film 7/10 stars saying:
The charming coming of age comedy The Way Way Back soundtracks its tale of 14-year-old Duncan's fateful summer working at the Water Wizz water park with bouncy '80s hits and indie rock. ... While the collection isn't as consistent as the soundtracks to like-minded films such as Juno or Little Miss Sunshine, it still has enough personality to be an entertaining set of songs.
- "Can't Fight This Feeling" – REO Speedwagon