A Streetcar Named Desire takes place in a racially mixed area of New Orleans called Elysian Fields. A refined-looking school teacher named Blanche comes to visit her sister Stella and brother-in-law Stanley. Stella and Stanley live in a first-floor, two-room apartment. As Blanche waits alone in the apartment for her sister to arrive, she sneaks a drink of liquor. Soon Stella comes and greets her sister warmly. However, despite Blanche's friendliness, she seems to have an underlying nervousness. Blanche claims she was given a leave of absence from her teaching position to rest her nerves.
Blanche reveals that their family lost their home, a plantation called Belle Reve (from the French meaning "beautiful dream"). Blanche seems bitter toward Stella for leaving Belle Reve and going to New Orleans. Blanche feels she was left with all the responsibility of holding on to the estate. After a series of deaths in the family and a foreclosure on the mortgage, Blanche had to let Belle Reve go.
Stanley arrives. Blanche's demure manners contrast sharply with his crude, working-class manners. Stella tells Stanley she and Blanche are going out to dinner and a movie. Stanley becomes upset when he learns Blanche lost Belle Reve. He suspects Blanche sold the estate and kept the money. Stanley believes in the Napoleonic Code, which means he thinks all his wife's property belongs to him and vice versa. So he feels he is part owner of Belle Reve and wants to find out what happened to it. Stanley confronts Blanche about the plantation. Blanche shows Stanley her business papers and says Belle Reve was lost because its mortgage was foreclosed. Somewhat appeased, Stanley mentions Stella is pregnant. Happy for Stella, Blanche leaves with her sister for the restaurant.
Early in the morning Stanley and his friends Mitch, Steve, and Pablo play poker in the Kowalski kitchen. Stanley seems annoyed because he's losing. Stella and Blanche return from their night out and go into the bedroom. Blanche turns on the radio. Stanley orders her to turn it off. When she doesn't, Stanley turns it off himself. Mitch leaves the game and goes into the bedroom to talk to Blanche. They have a friendly conversation, and they learn that neither of them is married. Blanche turns on the radio again. Furious Stanley storms into the bedroom and throws the radio out the window. When Stella objects to his behavior, he hits her. Upset, Stella and Blanche leave the apartment and go to Eunice's apartment on the second floor. Stanley's friends calm him down. Filled with remorse Stanley goes outside and calls Stella. He keeps shouting her name until Stella comes down. She and Stanley embrace. Stanley carries her into the bedroom.
While Stanley is out, Blanche tries to convince Stella to leave her husband because of the brutish way he treats her. However Stella seems content after making love with Stanley the previous night. She thinks Blanche is overreacting and has seen Stanley at his worst. Blanche is shocked by her sister's nonchalant attitude about Stanley hitting her. Blanche considers contacting an old college friend named Shep, who is a millionaire, and asking him for a loan so she and Stella can leave and start a business. Stella sees no reason to leave her husband. Stanley returns to the house and secretly listens to Blanche and Stella's conversation. Blanche calls Stanley a subhuman animal and encourages Stella to leave him. Stanley then goes back out and reenters his house, pretending he has just arrived.
Stanley tells Blanche that a guy named Shaw says he had met Blanche at the Hotel Flamingo in Laurel, Blanche's hometown. This news flusters Blanche, but she denies ever going to a seedy place like the Flamingo. Stanley leaves. Almost panicking, Blanche asks Stella if she has heard any gossip from Laurel. Surprised at Blanche's nervousness, Stella says she's heard nothing and leaves to join Stanley. Alone in the apartment, Blanche flirts with a young man who has come to collect money for a newspaper. She kisses him on the lips. Dumbfounded, the man leaves.
Mitch and Blanche return from a date at an amusement park, and she invites him into the apartment. Stella and Stanley have not yet returned. Blanche pours a drink for Mitch, who seems to be infatuated with her. Blanche complains about the rude way Stanley treats her and claims the only reason she stays is because her sister is going to have a baby. Mitch says he doesn't think Stanley understands Blanche. Mitch says he told his mother how much he likes Blanche. Blanche asks if Mitch is sincere about his feelings for her, and Mitch says he is. Blanche tells him how years earlier she married a young man she loved deeply. One day, though, she found her husband in a sexual situation with another man. That evening, while out dancing with her husband, Blanche told him that he disgusted her. Her husband went outside and shot himself dead. Mitch says it sounds as if both he and Blanche need somebody. They kiss.
Months later Stella gets Blanche's birthday dinner ready while Blanche takes a bath. Stanley tells his wife that Blanche has been lying to them. Blanche stayed frequently at the Hotel Flamingo, where she had affairs with several men. Her behavior became notorious in Laurel. Also Blanche had sex with one of her high school students. When the school administration found out, they fired Blanche from her teaching position. Stella refuses to believe these stories, but Stanley claims he has verified them. Stanley has also told Mitch the same information, and he tells Stella not to expect Mitch to come to the birthday party. Blanche comes out of the bathroom and realizes from Stella's expression that something has happened.
In the Kowalski kitchen, Blanche, Stella, and Stanley finish Blanche's birthday dinner. Mitch does not show up. Stanley gets mad at his wife for calling him a slob and throws his plate and cup on the floor. Blanche thinks her sister might know why Mitch did not come, but Stella says she knows nothing. Blanche calls Mitch on the phone and leaves a message. Stanley tells Stella that everything will be better once Blanche leaves. Stanley gives Blanche a "birthday present"—a one-way ticket back to Laurel. Upset, Blanche runs into the bathroom. Stella feels birth pains and tells Stanley to take her to the hospital.
Alone in the apartment, Blanche sits hunched in a chair. Mitch, who is half-drunk, visits her. He acts coldly toward her and calls her a liar, then mentions her outrageous behavior in Laurel. Blanche admits to having affairs with strangers and says she was driven by panic. Mitch embraces her, asking Blanche to have sex with him. She begs him to marry her instead. Mitch says Blanche isn't clean enough to bring home to his mother. Blanche screams, causing Mitch to leave.
Blanche drinks liquor and packs her bags. Stanley comes back from the hospital to get some sleep. Stella won't give birth until the next morning. Blanche pretends to have received an invitation from Shep to go on a cruise and claims Mitch came back to apologize. Stanley mocks Blanche and says he's known from the start that she is a liar. He approaches her menacingly, and she breaks a bottle to defend herself. When Stanley lunges at her, Blanche takes a swipe at him with the bottle's jagged edge. He grabs her wrist, forcing her to drop the bottle. He then forces her onto the bed.
Weeks later, Stanley, Mitch, Steve, and Pablo play poker in the kitchen. In the bedroom Stella talks to her friend Eunice. Stella has made arrangements to take Blanche to a state mental hospital but has told Blanche that Shep is going to take Blanche away. Stella couldn't believe Blanche's story about Stanley raping her because Stella wants to preserve her marriage. When Blanche comes out of the bathroom, Stella and Eunice pretend they are getting Blanche ready to go on a vacation.
Blanche seems to have a tentative hold on reality. She talks about dying from eating an unwashed grape as if she knows this will happen. The Doctor and Matron from the state mental hospital arrive. Stella pretends the Doctor is Shep. However, when Blanche sees the Doctor, she knows he is not Shep and refuses to leave. Stanley gets up from the poker table and asks in an intimidating way if Blanche forgot something. Blanche says she has. The Matron grabs Blanche, who struggles with her. Stella can't stand to watch and goes outside, where she is comforted by Eunice. The Doctor pretends to be a gentleman asking Blanche out for a walk. His approach calms her down, and he escorts Blanche out of the apartment. Stella sobs uncontrollably. Eunice hands Stella's baby to her. Stanley tries to soothe his wife, who will not be consoled.