About five minutes into the film, Dorothy sings the song after failing to get her aunt and uncle to listen to her relate an unpleasant incident involving her dog, Toto, and the town spinster, Miss Gulch. Dorothy's Aunt Em tells her to "find yourself a place where you won't get into any trouble." This prompts Dorothy to walk off by herself, musing to Toto, "'Some place where there isn't any trouble.' Do you suppose there is such a place, Toto? There must be. It's not a place you can get to by a boat, or a train. It's far, far away. Behind the moon, beyond the rain..." at which point she begins singing.
The "Over the Rainbow" sequence, as well as the entirety of the Kansas scenes, was directed by King Vidor, though he was not credited. The song was initially deleted from the film after a preview in San Luis Obispo, because MGM chief executive Louis B. Mayer and producer Mervyn LeRoy thought it "slowed down the picture" and that "the song sounds like something for Jeanette MacDonald, not for a little girl singing in a barnyard." However, the persistence of associate producer Arthur Freed and Garland's vocal coach/mentor Roger Edens to keep the song in the picture eventually paid off. At the start of the film, part of the song is played by the MGM orchestra over the opening credits. A reprise of the song was deleted after being filmed. An additional chorus was to be sung by Dorothy while she was locked in a room in the witch's castle, helplessly awaiting death as the witch's hourglass ran out. However, although the visual portion of that reprise is presumably lost, the soundtrack of it survives and was included in the 5-CD Supreme Edition of the film's soundtrack, released by Rhino Entertainment. In that extremely intense and fear-filled rendition, Dorothy weeps her way through it, unable to finish, concluding with a tear-filled, "I'm frightened, Auntie Em – I'm frightened!" This phrase was retained in the film and is followed immediately by Aunt Em's brief appearance in the witch's crystal, where she is soon replaced by the visage of the witch (Margaret Hamilton), mocking and taunting Dorothy before turning toward the camera to cackle.
Judy Garland first recorded the song on the MGM soundstages on October 7, 1938, using an arrangement by Murray Cutter. A studio recording of the song, not from the actual film soundtrack, was recorded and released as a single by Decca Records in September 1939. In March 1940, that same recording was included on a Decca 78-RPM four-record studio cast album entitled The Wizard of Oz. Although this is not the version of the song featured in the film, Decca would continue to re-release the so-called "Cast Album" well into the 1960s after it was re-issued as a single-record 331⁄3 RPM LP. It was not until 1956, when MGM released the true soundtrack album from the film, that the film version of the song was made available to the public. The 1956 soundtrack release was timed to coincide with the television premiere of the movie. The soundtrack version has been re-released several times over the years, including in a "Deluxe Edition" from Rhino Records in 1995.
'Over the Rainbow' has become part of my life. It's so symbolic of everybody's dreams and wishes that I'm sure that's why some people get tears in their eyes when they hear it. I've sung it thousands of times and it's still the song that's closest to my heart.
Following the film's release in 1939, "Over the Rainbow" became Garland's signature song and she would perform it for the next thirty years, until her death in 1969. Garland performed the song without altering it, singing exactly as she did for the movie. She explained her fidelity by saying that she was staying true to the character of Dorothy and to the message of really being somewhere over the rainbow.
An introductory verse ("When all the world is a hopeless jumble…") that was not used in the movie is often used in theatrical productions of The Wizard of Oz and is included in the piano sheet music book of songs from the film. It was also used in renditions by Frank Sinatra, Doris Day on her 1958 album Hooray For Hollywood (Vol.1), Tony Bennett on his 1961 album Tony Bennett Sings A String Of Harold Arlen,Ella Fitzgerald, Sarah Vaughan, and Norma Waterson (among others). Garland herself sang the introductory verse only once, on a 1948 radio broadcast of The Louella Parsons Show. Lyrics for a second verse ("Once by a word only lightly spoken…") appear in the British edition of the sheet music.
A second bridge is also used occasionally in theatrical productions. The short reprise, deleted from the final cut of the film, uses the melody of the bridge (or "B" section). Pop singer Pink performed the song with the introductory verse at the 86th Academy Awards on March 2, 2014, in celebration of the 75th anniversary of The Wizard of Oz .
The song has been translated into Esperanto twice. The first translation was by Londoner Harry Holmes. The second, more recent, translation is by Pejno Simono.
Australian band Billy Thorpe and The Aztecs' version topped the Australian music charts in 1965 and a later revision of the song also charted in 1974 following Billy Thorpe's blues-based revival of the song at the 1973 Sunbury Pop Festival.
Israel Kamakawiwoʻole's album Facing Future, released in 1993, included a ukulelemedley of "Over the Rainbow" and Louis Armstrong's "What a Wonderful World". The song reached #12 on Billboard's Hot Digital Tracks chart the week of January 31, 2004 (for the survey week ending January 18, 2004). In the UK the song was released as a single under the title "Somewhere Over the Rainbow". It entered the UK Official Singles Chart in April 2007 at #68. After several returns to the chart, in September 2008 it reached its peak position so far going up to #46. In Germany, the single also returned to the German Singles Chart in September 2010. After only 2 weeks on that chart, the song had already received gold status for having sold 150,000 copies. In October 2010 the song reached No. 1 in the German charts and 2011 it has been certified 5x Gold for selling more than 750,000 copies. It stayed 12 non-consecutive weeks at the top spot and was the most successful single in Germany in 2010. As of March 2012, it's the 2nd best-selling download ever in Germany with digital sales between 500,000 and 600,000. In France, the song debuted at #4 in December 2010 and reached number one. In the USA, the song was certified Platinum for 1,000,000 downloads sold. To date the song has sold over 4.2 million digital copies as of October 2014. In Switzerland, the song received Platinum, too, for 30,000 copies sold.
This version of the song was recorded in 1988, in Honolulu in just one take. Israel called the recording studio at 3am. He was given 15 minutes to arrive by Milan Bertosa. Bertosa is quoted to say ″And in walks the largest human being I had seen in my life. Israel was probably like 500 pounds. And the first thing at hand is to find something for him to sit on." The building security found Israel a big steel chair. "Then I put up some microphones, do a quick sound check, roll tape, and the first thing he does is 'Somewhere Over the Rainbow.' He played and sang, one take, and it was over." 
Eva Cassidy recorded a version of the song for the 1992 Chuck Brown/Eva Cassidy album The Other Side. After Cassidy's death in 1996, the song was included in her posthumously-released compilation album Songbird, released in 1998 and was released as a CD single in 2001. This version was popularised by the BBC on BBC Radio 2 and on the television show Top of the Pops 2; the latter featured a video recording of Cassidy performing the song. This publicity helped push sales of the compilation album Songbird to #1 in the UK charts. Eva Cassidy's unique rendition of "Over the Rainbow" was selected by the BBC in the UK for their Songs of the Century album in the year 1999. Cassidy's performance of "Over the Rainbow" at Blues Alley was published for the first time in January 2011 on her Simply Eva album.
Danielle Hope, the winner of the Wizard of Oz-themed BBC talent show Over the Rainbow, released a cover version of the song. The song was released by digital download on 23 May 2010 and a CD single was released on 31 May 2010. As the song was recorded before a winner was announced, runners-up Lauren Samuels and Sophie Evans also recorded versions of the song. These were both later made available for download on 6 June 2010. All three finalists appeared on the CD single's B-side: a Wizard of Oz medley.
The single was a charity record, raising money for both the BBC Performing Arts Fund and Prostate UK.
^"Israel Kamakawiwo'ole: The Voice Of Hawaii". 50 Great Voices. NPR. 6 December 2010. Archived from the original on 9 March 2011. Retrieved 16 December 2015. Then I put up some microphones, do a quick sound check, roll tape, and the first thing he does is 'Somewhere Over the Rainbow.' He played and sang, one take, and it was over.