Frat House is a 1998 documentary that explores the darker side of fraternity life and hazing. The film, directed by Todd Phillips and Andrew Gurland, focuses on the pledging process through a composite of different fraternities. It was mostly filmed at the Alpha Tau Omega fraternity house at Muhlenberg College in Allentown, Pennsylvania. Alpha Tau Omega's charter was revoked two years later in 2000, though it has since been reinstated. The documentary also features scenes of the Beta Chi and Tau Kappa Epsilon fraternities on the campus of SUNY Oneonta in Oneonta, New York.

The film premiered at the 1998 Sundance Film Festival to acclaim, winning the Grand Jury Prize for Documentary. HBO Films acquired the distribution rights and planned to air it that year, but after subsequent allegations that some of the film's content was staged for the camera, as well as concerns from fraternity members about their depiction in the film, HBO cancelled the airing. The film never received an official release, though bootleg versions have occasionally circulated online.

In an opening voiceover, co-director Todd Phillips says he was told that a film like this couldn't be made.

At SUNY Oneonta, Phillips and co-director Andrew Gurland meet a fraternity brother of Beta Chi who goes by the name of Blossom. Blossom tells the cameras that hazing is "like having the power of a god," and that one of his frat's hazing rituals includes biting the head off a rat. The film shows a candlelit initiation ceremony where new pledges are taught the fraternal code. In voiceover, Phillips says the point of this is to make the pledges feel like they already belong and that good times are ahead. However, the formalities are intended to motivate the pledges to endure the imminent process of hazing.

During the pledges' Hell Week, they are forced to wear uniforms, wake up at all hours, engage in strenuous physical activities, and chug beers on demand. In his voiceover, Phillips reveals that some frat members have grown uncomfortable with outsiders filming their exploits. Phillips decides to take a risk and shows up to a skeptical frat house unannounced. When he and his crew arrive, they discover pledges being blindfolded and tricked into believing they'll be branded with a hot iron. Shortly after witnessing this, Phillips and company are kicked out and told they can no longer film at the frat house. Blossom tells Phillips it's best if the film crew leaves town and ceases production. Some frat members then trash the crew's production van, painting the word "Die" on its side. When Phillips calls Blossom for an explanation, Blossom threatens to kill him.

After giving up on filming at Blossom's fraternity, Phillips and Gurland go to Muhlenberg College in Allentown, Pennsylvania and meet with a second fraternity. When they explain to the brothers of Sigma Alpha Mu, also known as "Sammy", that they are filming a documentary on fraternity life, the brothers allow them to film the entirety of their hazing rituals on the condition that they participate in the pledging process. For Phillips, this involves being locked inside a dog crate where he has beer, spit, and cigarette ashes thrown on him. Gurland's experience lands him in a hospital due to stomach pain and he drops out of the proceedings.

Phillips said it was not his or Gurland's intention as filmmakers to make a "sweeping [exposé] about fraternities or [make a case] that they should be outlawed." He said, "The movie is about hazing and rituals and the things men go through to belong. Everybody's so afraid of standing out in this world that they will even get beat up and peed on and thrown up on just to be part of a group, which is pathetic." Phillips said the intention was for viewers to come away with a better understanding of why people would put themselves through the mental and physical anguish of hazing in order to belong.

Said Phillips, "When you actually go through the hazing, you sort of understand why they do it. It really does increase the bonding with your fellow pledges, like going through a war. That's really what they're trying to do. They're not trying to lock people in trunks and kill them. They're trying to form a bond that will outlast college."