In 2005, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".

Plot
Jordan "Bick" Benedict (Rock Hudson), the head of the rich Benedict ranching family of Texas, goes to Maryland to buy a stud horse, War Winds. There he meets and courts the socialite Leslie Lynnton (Elizabeth Taylor), who breaks off her engagement to a diplomat (Rod Taylor) and becomes Bick's wife.

They return to Texas to start their life together on the family ranch, Reata, where Bick's sister Luz (Mercedes McCambridge) runs the household. Luz resents Leslie's arrival and tries to intimidate her. Jett Rink (James Dean) works for Luz and hopes to find his fortune by leaving Texas; he also has a secret love for Leslie. Luz expresses her hostility for Leslie by cruelly digging in her spurs while riding Leslie's beloved horse, War Winds. Luz dies after War Winds bucks her off, and as part of her will, Jett is given a plot of land within the Benedict ranch. Bick tries to buy back the land, but Jett refuses. Jett keeps the fenced off waterhole as his home and names the property Little Reata. Leslie eventually gives birth to twins, Jordan "Jordy" Benedict III (Dennis Hopper) and Judy Benedict (Fran Bennett), and a younger daughter named Luz II (Carroll Baker).

Jett discovers traces of oil in a footprint left by Leslie and he drills in the spot. He hits his first gusher and is covered in the spouting oil. He drives to the Benedict front yard to assert himself and proclaim to the family and guests that he will be richer than the Benedicts. After Jett makes a rude sexual remark to Leslie, Bick punches him. As Bick's friends restrain him, Jett hits him several times, then drives off. In the years before World War II, Jett prospers through his oil drilling company, named 'Jetexas'. Determined to remain a cattle rancher like his forefathers, Bick rejects several offers to drill for oil on his much larger ranch.

Meanwhile, tensions in the Benedict household revolve around how the parents want to bring up their children. Bick insists that Jordy must succeed him and run the ranch, as his father and grandfather before him – but Jordy wants to be a doctor. Leslie wants Judy to attend finishing school in Switzerland, but Judy loves the ranch and wants to study animal husbandry at Texas Tech. Both children succeed in pursuing their chosen vocations. After war breaks out, Jett visits the Benedicts to persuade Bick to allow oil production on his land to help the war effort. Recognizing that his children will not take over the ranch when he retires, Bick concedes. Both Bick and Jett have developed drinking problems. Luz II, now in her teens, starts flirting with Jett. Once oil production starts on the ranch, the wealthy Benedict family becomes even wealthier, as suggested by the addition of a swimming pool next to the house.

After the war, the Benedict-Rink rivalry continues, coming to a head when the Benedicts discover that Luz II and the much older Jett have been dating. At a huge gala Jett organizes in his own honor, an irate Jordy tries to fight him after his Mexican-American wife, Juana (Elsa Cárdenas), is repeatedly insulted by Jett's employees because of her race. As his goons hold Jordy, Jett punches him repeatedly in front of a crowd, and has the young man thrown out. Fed up, Bick challenges Jett to a fistfight. Drunk and almost incoherent, Jett leads the way to a wine storage room. Seeing that Jett is in no state to defend himself, Bick lowers his fists, says "You're not even worth hitting. ... You're all through," and leaves, but not before toppling Jett's wine cellar shelves, domino-style. Jett, completely drunk, collapses face down and falls asleep on the table in front of his seat of honor. All the guests leave. Later, Luz II sees him partly recovered from his stupor, talking to an empty room and disclosing that his sexual interest in the young girl is only his attempt to possess her mother symbolically.

The next day, the Benedicts, all except Jordy, drive down a sparsely traveled road and stop at a segregated diner. Juana and her little boy are once again insulted racially, and when the proprietor, Sarge (Mickey Simpson), insults and begins to physically eject an old Mexican man and his family, Bick tries to stop him. This leads to a fistfight, which Bick clearly loses. Juana, Leslie and Luz II are disgusted by Sarge's bigotry, but proud of Bick for standing up to the bully.

Back at the ranch, Bick and Leslie watch their grandchildren, blonde and Latino, and reflect on their life and family. Leslie tells Bick that after watching him lose the fight in the diner, she respects his evolution in understanding the concerns of people not like his wealthy forbears, and considers their own incarnation of the Benedict family a success.

Reception
Giant won praise from both critics and the public, and according to the Texan author, Larry McMurtry, was especially popular with Texans, even though it was sharply critical of Texan society. Bosley Crowther of the New York Times wrote that "[George Stevens] takes three hours and seventeen minutes to put his story across. That's a heap of time to go on about Texas, but Mr. Stevens has made a heap of film." and 'Giant', for all its complexity, is a strong contender for the year's top-film award."

Variety's "Hift" claimed that Giant was "for the most part, an excellent film which registers strongly on all levels, whether it's in its breathtaking panoramic shots of the dusty Texas plains; the personal, dramatic impact of the story itself, or the resounding message it has to impart."

The film received a 97% positive rating on the film-critics aggregate site Rotten Tomatoes. TV Guide gave the film its maximum of four stars, saying of James Dean's performance "This was the last role in Dean's all-too-brief career – he was dead when the film was released – and his presence ran away with the film. He performs his role in the overwrought method manner of the era, and the rest of the cast seems to be split between awe of his talent and disgust over his indulgence."

The movie earned $12 million in rentals in North America during its initial release.

Academy Awards
Giant won the Academy Award for Best Director and was nominated nine other times, twice for Best Actor in a Leading Role (James Dean and Rock Hudson). The other nominations came in the categories of Best Actress in a Supporting Role (Mercedes McCambridge); Best Art Direction–Set Decoration, Color (Boris Leven, Ralph S. Hurst); Best Costume Design, Color; Best Film Editing; Best Music, Scoring of a Dramatic or Comedy Picture; Best Picture; and Best Writing, Best Screenplay – Adapted.