Entertainment Weekly has called The Room "the Citizen Kane of bad movies" and a number of notable publications have labeled it as one of the worst films ever made. Originally shown only in a limited number of California theaters, the film quickly developed a cult following as fans found humor in the film's bizarre storytelling and various technical and narrative flaws. Although Wiseau has retroactively characterized the film as a black comedy, audiences have generally viewed it as a poorly made drama, a viewpoint supported by some of the film's cast. Within a decade of its premiere, the film was selling out showings around the United States and internationally. The film has also inspired a video game of the same name and a book entitled The Disaster Artist.
Johnny is a successful banker who lives in a San Francisco townhouse with his future wife, Lisa. They share an intense intimate relationship characterized by constant, passionate lovemaking. Despite this idyllic existence, Lisa has inexplicably become dissatisfied with her life, and one afternoon confides to her best friend Michelle and her mother Claudette that she finds Johnny boring. Although Michelle advises her to be grateful for what she has, and her mother counsels her that financial stability is more important than happiness, Lisa decides to seduce Johnny's best friend, Mark. Although he is initially reluctant, Mark gives in to Lisa's advances. Their affair continues through the remainder of the film, even though Mark appears reluctant at the outset of each sexual encounter and repeatedly tries to break off the relationship. Lisa, meanwhile, having come to the realization that she "wants it all", decides to stay with Johnny for financial support and the material goods he can provide her. As the wedding date approaches and Johnny's clout at his bank slips, Lisa alternates between glorifying and vilifying Johnny to her family and friends, both making false accusations of domestic abuse and defending Johnny against criticisms. Meanwhile, Johnny, having overheard Lisa confess her infidelity to her mother, attaches a tape recorder to their phone in an attempt to identify her lover.
Against the backdrop of Lisa and Mark's affair, numerous subplots involving secondary characters begin to develop: Denny, a neighboring college student whom Johnny financially supports and "loves like a son", has a mysterious run-in with an armed drug dealer named Chris-R, whom Johnny and Mark overpower and take to the police. Denny also lusts after Lisa, ultimately confessing to Johnny his attraction; once Johnny tells Denny that Lisa loves him as her friend, Denny resolves to propose to his own girlfriend. Johnny takes on a mysterious client at his bank whose identity he is sworn to protect. Claudette experiences real estate problems, bemoans failed relationships, and informs Lisa that she has breast cancer. Michelle and her boyfriend, Mike (Scott Holmes), break into Johnny and Lisa's home to have sex. Peter (Kyle Vogt), a psychologist friend of Johnny and Mark's, alternates between defending Lisa and assessing her as a sociopath, which results in Mark briefly trying to murder him. Each subplot receives little exposition, and none are ever resolved.
At a surprise birthday party for Johnny, Steven, a previously unseen friend of Lisa and Johnny's, catches Lisa kissing Mark while the rest of the guests are outside and confronts her about the affair. Lisa expresses no remorse, while Mark angrily urges Steven not to tell anyone. Johnny announces to the guests that he and Lisa are expecting a child, only for Lisa to tell Steven and Michelle that she lied about it in order to "make it interesting". At the end of the evening, Lisa flaunts her affair in front of Johnny, who physically attacks Mark.
After the party, Johnny locks himself in the bathroom, prompting Lisa to make plans to leave him for Mark. Johnny finally comes out of the bathroom and retrieves the cassette recorder he attached to the phone, and listens to an intimate call between Lisa and Mark. Claiming that all of his friends have betrayed him, Johnny destroys his apartment and then kills himself with the pistol earlier recovered from Chris-R. Denny, Mark and Lisa discover Johnny's body sometime later. Mark and Denny blame Lisa for Johnny's death, with Mark declaring he does not love Lisa and never wants to see her again. Denny asks Lisa and Mark to leave, but they stay and comfort one another as the sound of the approaching sirens grow louder.