The film is mostly in Technicolor, but its opening and closing sequences are in sepia-tinted black-and-white, including all of the film's credits. It was directed primarily by Victor Fleming. Noel Langley, Florence Ryerson and Edgar Allan Woolf received credit for the screenplay, but there were uncredited contributions by others. The lyrics for the songs were written by E.Y. Harburg, the music by Harold Arlen. Incidental music, based largely on the songs, was by Herbert Stothart, with borrowings from classical composers.

Although the film received largely positive reviews, it was not a huge box office success on its initial release, earning only $3,017,000 on a $2,000,000 budget. The film was MGM's most expensive production up to that time, but its initial release failed to recoup the studio's investment. Subsequent re-releases made up for that, however. It was nominated for six Academy Awards, including Best Picture. It lost that award to Gone with the Wind, but won two others, including Best Original Song for "Over the Rainbow". The song was ranked first in the AFI's 100 Years...100 Songs list.

Telecasts of the film began in 1956, re-introducing the film to the public and eventually becoming an annual tradition, making it one of the most famous films ever made.The film was named the most-watched motion picture in history by the Library of Congress, is often ranked among the Top 10 Best Movies of All Time in various critics' and popular polls, and is the source of many memorable quotes referenced in modern popular culture.

Plot
Kansas farm girl Dorothy Gale (Judy Garland) lives with her Aunt Em (Clara Blandick) and Uncle Henry (Charles Grapewin). Her guardians and the farmhands Hunk (Ray Bolger), Zeke (Bert Lahr) and Hickory (Jack Haley) are too busy to pay attention to her. Em then tells her niece to find a "place where she won't get into any trouble" causing her to sing "Over the Rainbow". Miss Gulch (Margaret Hamilton) shows up to have Dorothy's pet dog Toto destroyed after he bit her earlier on. Toto escapes though and Dorothy, knowing Miss Gulch will be back, decides to run away. They meet Professor Marvel (Frank Morgan), who claims via his crystal ball that Em is "sick". Believing him, Dorothy heads back to the farm, just as a tornado approaches. Her family and the hands are in the storm cellar when she arrives, and Dorothy, running into the farm house to look for everyone, is hit on the head by a window frame and knocked unconscious. Dorothy awakens and discovers that she and the house have been swept away and are soaring through the core of the tornado. The house eventually lands with a bump.

Dorothy and Toto enter a technicolor world named Oz and meet Glinda the Witch of the North (Billie Burke) who states that they are now in Munchkinland, and that Dorothy's house has killed the Wicked Witch of the East. The Munchkins rejoice that the Witch is dead but her evil sister, the Witch of the West (Margaret Hamilton) arrives and is furious both that her sister is dead and her dead sister's magical ruby slippers are now worn by Dorothy, thanks to Glinda. She promises vengeance on Dorothy and Toto before leaving. Glinda tells Dorothy she can get back to Kansas by following the yellow brick road to see the Wizard of Oz, who lives in the Emerald City.

Dorothy and Toto en route to the city encounter the Scarecrow (Ray Bolger), Tin Man (Jack Haley) and the bipedal Cowardly Lion (Bert Lahr) who wish for a brain, heart and courage respectively. As they approach the city, the Witch tries to kill Dorothy by spiking the poppy field with poison, but Glinda intervenes, much to the fury of the Wicked Witch. The friends eventually arrive at the city and are greeted by both the door keeper and coachman (both Frank Morgan). Dorothy and the Lion get makeovers, while Scarecrow gets fresh straw and the Tin Man, who up to now had been stained with rust, is polished. After the Witch sends a threatening message, they meet the Wizard's guard (Frank Morgan), who eventually gets them in to see the Wizard (Frank Morgan), who says he will grant their wishes for a service: bring him the Witch of the West's broom.

On their way to the Witch's castle, the flying monkeys ambush them and kidnap Dorothy and Toto. In the castle, the Witch blackmails Dorothy, threatening to drown Toto if she does not give her the slippers. After Dorothy agrees, the Witch is still unable to get them due to a shower of sparks. Toto escapes and the Witch locks Dorothy in the tower, planning to execute her once the top bulb of her hourglass is empty. Toto finds the trio and they overpower three Winkie guards before saving Dorothy, but are chased by the Witch and her other guards. They soon trap the foursome and the Witch sets Scarecrow afire. Dorothy, in putting out the flames with a bucket of water, accidentally splashes water over the Witch, causing her to melt. The Winkies are now free and reward Dorothy by giving her the broomstick.

Back in Emerald City, the Wizard still refuses to grant their wishes, but after Toto accidentally exposes him as a normal old man with no real magical powers, he says he will do so. He gives the Scarecrow a diploma, Lion a medal and Tin Man a heart-shaped clock. He decides to fly Dorothy home in his hot air balloon, but it takes off without her. Glinda arrives and tells her the ruby slippers will get her home. After saying her goodbyes, Dorothy clicks her heels three times and awakens back home surrounded by her family, the three farmhands and Marvel. She claims the hands and Marvel were in Oz and says, "There's no place like home", though it is implied Dorothy's visit to Oz was simply a dream.

Awards and honors
The film was nominated for several Academy Awards, including Best Picture and Best Visual Effects. In the Best Picture category, it lost to another MGM film, Gone with the Wind, another film directed by Victor Fleming. E.Y. Harburg and Harold Arlen won the award for Best Song (Over The Rainbow) and Best Original Music Score; composer Herbert Stothart received the Best Original Score Award. Garland received a special Academy Juvenile Award that year, for "Best Performances by a Juvenile" (the award was also for her role in the film version of Babes in Arms). The Wizard of Oz did not receive an Oscar for its special effects — that award went to the 1939 film version of The Rains Came. Additional nominations went to Cedric Gibbons and William A. Horning for Art Direction, and Hal Rosson for Cinematography (color), but both of those awards were won by Gone With the Wind. There was no award for makeup then, so Jack Dawn could not receive an award for his detailed makeup for the Oz fantasy characters.

In June 2008, AFI revealed its "Ten top Ten"—the best ten American films in ten genres—after polling over 1,500 film artists, critics and historians. The Wizard of Oz was acknowledged as the best film in the fantasy genre.

Cultural impact
Regarding the original Baum storybook, it has been said that "The Wonderful Wizard of Oz is America's greatest and best-loved home grown fairytale. The first totally American fantasy for children, it is one of the most-read children's books . . . and despite its many particularly American attributes, including a wizard from Omaha, The Wonderful Wizard of Oz has universal appeal."

The film also has been deemed "culturally significant" by the United States Library of Congress, which selected it for preservation in the National Film Registry in 1989. In June 2007, the film was listed on UNESCO's Memory of the World Register. The film placed at number 86 on Bravo's 100 Scariest Movie Moments.[64] In 1977, Aljean Harmetz wrote The Making of The Wizard of Oz, a detailed description of the creation of the film based on interviews and research; it was updated in 1989.

Quotes from the film such as, "I'm melting! I'm melting!", can be heard in numerous films such as Field of Dreams, The Matrix, Avatar, and Twister, as well as in numerous television shows.

Several quotes have made the AFI's 100 Years Top 100 Movies Quotes:
"Toto, I've got a feeling we're not in Kansas anymore." (4th)
"There's no place like home." (23rd)
"I'll get you, my pretty, and your little dog too!" (99th)

When Ray Bolger, the last survivor of the major players, died in 1987, a Chicago Tribune editorial cartoon portrayed the Scarecrow running over the rainbow to catch up with the other characters.