Step Brothers is a 2008 American comedy film directed by Adam McKay, produced by Jimmy Miller and Judd Apatow, and written by Will Ferrell and McKay from a story by Ferrell, McKay, and John C. Reilly. It follows Brennan (Ferrell) and Dale (Reilly), two grown men who are forced to live together as stepbrothers after their single parents, with whom they still live, marry each other. Richard Jenkins, Mary Steenburgen, Adam Scott, and Kathryn Hahn also star. Ferrell notably sings "Por Ti Volaré" during the film's climactic scene while Reilly plays drums.

The film was released by Sony Pictures Releasing on July 25, 2008, two years after Talladega Nights: The Ballad of Ricky Bobby. Both films feature the same main actors, as well as the same producing and writing team. It grossed $128.1 million and received mixed reviews.

39-year-old Brennan Huff and 40-year-old Dale Doback are immature adults still living at home. Brennan lives with his divorced mother, Nancy, and Dale lives with his widowed father, Robert. Robert and Nancy meet, fall in love, and marry, forcing Brennan and Dale to live together as step brothers. Brennan and Dale initially despise each other, and after Brennan defies Dale's order not to touch his drum set, a fight erupts between them. They are grounded with no television for a week and are ordered to find jobs within a month or be evicted.

When Brennan's arrogant classist younger brother Derek, a successful helicopter leasing agent, visits with his family, he openly ridicules Dale and Brennan, and Dale punches him in the face. Brennan is awed that Dale stood up to Derek, while Derek's discontented wife Alice finds Dale's courage attractive, and begins a sexual affair with him, unbeknownst to Derek. Brennan and Dale bond over their shared tastes and interests, particularly music. Brennan had given up singing after Derek and his friends jeered his performance in a school musical. Robert, meanwhile, schedules several job interviews for them, but they perform poorly and then are attacked on their way home by school children. Robert and Nancy reveal that with Derek's help they plan to sell the house, retire and travel the world on Robert's sailboat. They also sign Brennan and Dale up for therapy and set up bank accounts for them to live off of until they find work. Brennan falls in love at first sight with his therapist, Denise, but the attraction is not mutual.

At Derek's birthday party, Dale and Brennan present a pitch video for their entertainment company, "Prestige Worldwide", that includes a music video, "Boats 'N Hoes", which they filmed on Robert's boat without his knowledge. The presentation backfires when the video shows the boat crashing, shattering Robert and Nancy's sailing dreams and straining their marriage. On Christmas, Robert and Nancy announce they are getting divorced, upsetting Brennan and Dale, who blame each other. Brennan and Dale go their separate ways, live independently and gradually become functioning adults.

Brennan gets a job at Derek's helicopter leasing firm and volunteers to oversee a prestigious event, the Catalina Wine Mixer. He hires the catering company that employs Dale and invites Robert and Nancy to attend. The party goes well until the lead singer of the hired Billy Joel cover band loses his temper with a heckler and is hustled away. Derek blames Brennan for the fiasco and fires him. Robert encourages Brennan and Dale to be their eccentric child-at-heart selves again and perform to save the party. The pair take the stage and Brennan sings "Por Ti Volaré" while Dale accompanies him on drums. Brennan's moving performance brings the extended family back together and entrances Denise. Dale, meanwhile, breaks off his relationship with Alice.

Six months later, Robert and Nancy are back together living in their old house, while Brennan and Dale have turned "Prestige Worldwide" into a successful entertainment company that owns six karaoke bars and two karaoke restaurants. As a Christmas surprise, Robert has turned his boat into a tree house for Brennan and Dale to play in, complete with hats and masks. Denise, who has come to the dinner with Brennan, admires the way he looks in a pirate hat. During the ending credits, Dale and Brennan exact their revenge on the schoolyard bullies.

• Will Ferrell as Brennan Huff
  • Bryce Hurless as young Brennan Huff
• John C. Reilly as Dale Doback
• Mary Steenburgen as Nancy Huff
• Richard Jenkins as Dr. Robert Doback
• Adam Scott as Derek Huff
  • Dmitri Schuyler-Linch as young Derek Huff
• Kathryn Hahn as Alice Huff
• Andrea Savage as Denise
• Lurie Poston as Tommy Huff
• Elizabeth Yozamp as Tiffany Huff
• Logan Manus as Chris Gardocki
• Travis T. Flory as Redheaded Kid
• Shira Piven as Nurse
• Seth Morris as Doctor
• Wayne Federman as Blind Man
• Maria Quiban as TV Anchor
• Danielle Schneider as Receptionist
• Gillian Vigman as Pam Gringe
• Brian Huskey as Interviewer
• Seth Rogen as a Sporting Goods Manager
• Chris Henchy as First Homebuyer
• Mary Catherine Hamelin as First Homebuyer
• Ian Roberts as Male Therapist
• Phil LaMarr as Second Homebuyer
• Erica Vittina Phillips as Second Homebuyer
• Rob Riggle as Randy
• Ken Jeong as Employment Agent
• Horatio Sanz as Lead Singer
• Jake Szymanski as Caterer
• Matt Walsh as Drunk Corporate Guy
• Brent White as Therapy Patient

Step Brothers was released in the United States on July 25, 2008.

The film was released for home video on December 2, 2008, in a single-disc rated edition, a single-disc unrated edition and a 2-disc unrated edition. The film generated sales of an estimated 3.87 million units in DVD and Blu-ray, totaling $63.7 million. For the home video release, Will Ferrell, John C. Reilly, and Adam McKay recorded a commentary track mostly in song, accompanied by Jon Brion; the track covers "the movie-making process [and] their characters' offscreen lives" in remarks that range "from the inspired to the irritatingly prolonged, but when Ferrell and Reilly really get into a good groove, they're actually funnier than the main feature". Step Brothers was released on 4K Blu-Ray on October 2, 2018.

Step Brothers opened in 3,094 theaters and grossed $30.9 million. It went on to gross $100,468,793 domestically and $27,638,849 internationally for a total of $128,107,642.

Step Brothers received mixed reviews from critics. On Rotten Tomatoes, the film has an approval rating of 55% based on 205 reviews, with an average rating of 5.60/10. The site's critical consensus reads, "Step Brothers indulges in a cheerfully relentless immaturity that will quickly turn off viewers unamused by Ferrell and Reilly -- and delight those who find their antics hilarious." On Metacritic, the film has a weighted average score of 51 out of 100, based on 33 critics, indicating "mixed or average reviews". Audiences surveyed by CinemaScore gave the film a grade "B" on scale of A to F.

Roger Ebert gave the film 1.5 out of 4 stars and stated, "When did comedies get so mean? Step Brothers has a premise that might have produced a good time at the movies, but when I left, I felt a little unclean".

Ty Burr in the Boston Globe wrote, "'Step Brothers' is crudely funny, which means that sometimes it's crudely hilarious and more often it's just crude." Variety critic John Anderson wrote, "the film is funny at times but lapses into the reflexive vulgarity that seems to be the default mechanism of the Apatow machinery."

In the British Film Institute's 2012 Sight & Sound polls of the greatest movies ever made, The Snowtown Murders and Macbeth director Justin Kurzel named Step Brothers one of his 10 favorite films.

In the movie, Dale and Brennan make a video to pitch both Robert and Derek about investing in Prestige Worldwide, with a music video for a song titled "Boats 'N' Hoes". Since the release of the film, "Boats 'N' Hoes" has contributed to the success of the movie with over a million hits on YouTube and merchandise that references the song.

A political action committee (PAC) known as the "Boats 'N' Hoes PAC" was registered by Shaun Nowacki with the Texas Ethics Commission in 2014. Nowacki's firm was hired by multiple Republicans in Texas including 48th Texas Governor Greg Abbott, Dan Patrick (who was running for Lieutenant Governor), and Donna Campbell (who was campaigning for State Senator). The purpose of the PAC was never shared and was criticized by Lisa Paul, who served as the Texas Democratic Party Deputy Communications Director. Paul said, "Texas Republicans say they want to reach out to women, to be more inclusive, but actions like this reinforce a pattern of disrespect... Their contempt towards women is simply unforgivable."

The Catalina Wine Mixer event depicted in the film was not a real event that existed before or during the creation of the film. The event has since been created and hosted on Catalina Island on Descanso Beach.

McKay announced on Twitter in 2011 that production of a Step Brothers rap album featuring Ferrell and Reilly had begun, but later said that the rap album fell apart and will not be released.

Over the years, Ferrell and Reilly have talked about a sequel. Reilly had the idea. In 2008, McKay was interviewed about a possible sequel, and said:

We're kicking around the idea of Step Brothers 2. We feel like there's way more fat to be mined there. While it is not quite the legend that Anchorman is, it has built kind of a nice following. We think it could be a pretty fun one.

He added that Ferrell and Reilly's characters would be mature and have jobs. "One of them's married and has a kid. They're still kind of goofballs but they've taken three or four steps. Then we have an idea for something happens that knocks him back to square one, and one of the brothers, John C. Reilly sort of instigates it, like 'we can't take this anymore.' And things go really bad, their lives kind of fall apart. They have to pull it back together is sort of the basic structure." McKay has also said that ideas that were not used in the first film may be used in the sequel.

McKay spoke to Empire in February 2014 and appeared to rule out a sequel to Anchorman 2 or Step Brothers saying, "No, that's the last sequel we're gonna do. There's nothing more fun to me than new characters and a new world. And now we're releasing this alt version, we're totally satisfied. No Anchorman 3."

In a 2014 interview with Collider, McKay indicated the door was still open for a Step Brothers sequel at some point, while making clear it wasn't a short-term development priority, stating:

We have a whole story [for Step Brothers 2], an outline that we're happy with. We were ready to go, and you know the story of [how] we got the call on Anchorman 2. We're not gonna do it now 'cause we just did a sequel, I don't wanna get into the sequel business too much. It was kind of a novelty to do one of them and it was certainly very interesting and I had never done anything like it. So I want to go make some original movies—or you know, The Big Short is an adaptation but do some different stuff. But who knows? 2–3 years, 3–4 years. I mean the funny thing with Step Brothers is if those guys are in their 50s it still works, so we could easily return to that, but for now no sequels.

In February 2017, Ferrell said in an interview with Rolling Stone that there are currently no plans for a sequel to Step Brothers.

In November 2020, Reilly said in an interview on Conan of a sequel:

Like a lot of artists, all three of us felt like 'Unless we were really sure we could make a better version or improve on what it is, let's leave it alone.' Sequels are hard to pull off.

• List of Christmas films

• Step Brothers official website
• Step Brothers at IMDb
• Scoring Session Photo Gallery at ScoringSessions.com