Eloise Larkin and her fiancé Arthur's plans to attend the rehearsal of a play are jeopardized because no one will babysit her obnoxious kid brother Donald. Eloise phones the Cosman Employment Agency, where Mr. Dinkle and Jack are seeking work. Jack flirts with Cosman employee Polly, but he is thwarted by the arrival of her boyfriend, a towering police officer. Polly sends Dinkle and Jack to babysit, but an attempt to lull the boy to sleep by reading the fairy tale "Jack and the Beanstalk" aloud fails when Jack stumbles over the larger words. Bemused by Jack, Donald reads the story instead, a role-reversal made complete when Jack falls asleep as Donald reads. In his slumber, Jack dreams that he is the young Jack of the fairy tale.

In his dream, Jack learns that a giant who lives in a castle in the sky and has taken all of the kingdom's food as well as the crown jewels. The dire situation obliges the kingdom's princess to marry a prince from a neighboring kingdom whom she has never met. Jack must also make sacrifices. His mother sends him to sell the last family possession, their beloved cow Henry, to the local butcher, Mr. Dinklepuss. Along the way, Jack meets the prince, disguised as a troubador, who is kidnapped by the giant soon afterward. The unscrupulous Dinklepuss pays Jack five "magic" beans for the cow. Upon returning home, Jack learns that the giant has also kidnapped the princess and Henry.

Jack's mother, exasperated over the beans, tells Jack to plant them and a gigantic beanstalk grows overnight. He climbs the beanstalk to rescue everyone from the giant's clutches and retrieve Nellie, the golden-egg-laying hen that the giant had previously stolen from Jack's family. Upon learning of Nellie's existence, Dinklepuss joins Jack on the adventure. When they reach the top of the beanstalk, Jack and Dinklepuss are captured by the giant and imprisoned with the prince and princess. The princess falls for the troubador only to later learn that it is the same prince to whom she was betrothed.

The giant releases Dinklepuss and Jack from the dungeon in order to toil around his castle. They befriend his housekeeper Polly, who helps them escape over the castle wall along with the royal prisoners, Nellie and some of the giant's stolen gems (pilfered by the greedy Dinklepuss). They flee down the beanstalk with the giant in pursuit. During the descent, Dinklepuss loses Nellie (who falls into the arms of Jack's mother) and then the gems, which rain down upon the impoverished townsfolk below. Once all reach the ground, Jack chops the beanstalk, sending the giant falling to his death. The villagers rejoice by dancing around the hole left when the giant fell.

Just before being rewarded by the king for heroism, Jack is rudely awakened when Donald breaks a vase over Jack's head just as Eloise and Arthur return home from rehearsal. Jack cries out but receives a second blow to the head from Dinkle, which returns Jack to his dream state. After greeting Eloise and Arthur as their storybook counterparts, Jack dances off into the night.

• Bud Abbott as Mr. Dinkle/Mr. Dinklepuss
• Lou Costello as Jack/Jack Strong
• Dorothy Ford as The Receptionist/Polly
• Buddy Baer as Police Sergeant Riley/The Giant
• Shaye Cogan as Eloise Larkin/The Princess
• David Stollery as Donald Larkin
• James Alexander as Arthur/The Prince
• Barbara Brown as Mrs. Strong
• William Farnum as The King
• Arthur Shields as Patrick the Harp
• Johnny Conrad and Dancers
• Mel Blanc provides the voices of the woodland animals of the Giant's land.^[3]

When Universal-International refused to finance the color photography of the film, Abbott and Costello, whose contract allowed them one independent film per year, produced the film through Costello's company, Exclusive Productions. Abbott's company, Woodley Productions, produced a second color film, Abbott and Costello Meet Captain Kidd, in 1952. Warner Bros. distributed both films but did not provide financing or production services.^[4]

Jack and the Beanstalk was filmed from July 9 through August 2, 1951 at Hal Roach Studios using sets from Joan of Arc (1948).^[4] As with The Wizard of Oz, the film's opening and closing segments are presented in sepia tone, although many DVD releases present the sequences in black-and-white. The main portion of the film was filmed in Eastmancolor and presented in the SuperCineColor process (Eastmancolor in subsequent releases).

Songs written by Lester Lee and Bob Russell:

• "Jack and the Beanstalk"
• "I Fear Nothing"
• "Dreamer's Cloth"
• "He Never Looked Better in His Life"

A soundtrack, including songs and dialogue, was released by Decca Records on June 9, 1952.^[4]

Jack and the Beanstalk was rereleased in 1960 by RKO Pictures. The film rights were sold to RKO in the late 1950s. When RKO failed to renew the copyright in 1979, the film entered the public domain.^[5]

As Jack and the Beanstalk is in the public domain, it has been released multiple times on DVD by several companies. It was released on Blu-ray in 2008, 2015 and 2020.^[6] In 2020, a Kickstarter campaign to fund a Blu-ray restoration reached its $7,500 goal in two hours.^[7] ClassicFlix released the restoration on Blu-ray and DVD on July 26, 2022 in commemoration of the film's 70th anniversary.^[8]

• Jack and the Beanstalk at the American Film Institute Catalog
• Jack and the Beanstalk at IMDb  
• Jack and the Beanstalk at AllMovie
• Jack and the Beanstalk at the TCM Movie Database
• Jack and the Beanstalk is available for free viewing and download at the Internet Archive