"Rainbow Connection" is a song from the 1979 film The Muppet Movie, with music and lyrics written by Paul Williams and Kenneth Ascher. The song was performed by Jim Henson as Kermit the Frog during the film's opening number, where it opens with Kermit sitting alone on a log in the swamp, playing the song on his banjo. The song is an integral part of Kermit's character's arc, since it establishes his dream of "making millions of people happy," which motivates his journey to Hollywood throughout the film.

"Rainbow Connection" reached No. 25 on the Billboard Hot 100 in November 1979, with the song remaining in the Top 40 for seven weeks in total. Williams and Ascher received an Academy Award nomination for Best Original Song at the 52nd Academy Awards.

In 2020, "Rainbow Connection" was deemed "culturally, historically, or aesthetically significant" by the Library of Congress and selected for preservation in the National Recording Registry.

Williams and Ascher, who had previously collaborated on several songs for the 1976 film A Star Is Born, were tasked with writing the songs for The Muppet Movie. For the song that became "Rainbow Connection", Jim Henson told them that the opening scene should feature Kermit the Frog by himself, singing and playing the banjo. Williams and Ascher wrote most of the song fairly quickly at Williams's house but got stuck trying to think of appropriate words for the part in the chorus that eventually became the phrase "the rainbow connection"; they were looking for a way to tie in the chorus to the song's theme of rainbows. As they sat down for dinner with Williams's then-wife, Kate Clinton, they explained to her their predicament of looking for a phrase that would provide "a rainbow connection", then realized, in the course of explaining the problem to her, that the phrase "the rainbow connection" would itself be a good fit. Williams and Ascher used "When You Wish Upon a Star" from Pinocchio as inspiration for the song.

Williams has said that his favorite lyrics in the song are in the second verse, which begins with "Who said that every wish / Would be heard and answered / When wished on the morning star?", because they imply that "there's power in your thoughts". He also noted that the lyrical phrasing was written weirdly with Kermit's speech patterns in mind.

Allmusic described "Rainbow Connection" as an "unlikely radio hit ... which Kermit the Frog sings with all the dreamy wistfulness of a short, green Judy Garland" and went on to add that "'Rainbow Connection' serves the same purpose in The Muppet Movie that 'Over the Rainbow' served in The Wizard of Oz, with nearly equal effectiveness: an opening establishment of the characters' driving urge for something more in life." Others have similarly referred to "Rainbow Connection" as the film's "I Want" song.

Ascher and Williams received Oscar nominations at the 52nd Academy Awards for the score of The Muppet Movie and for "Rainbow Connection", which was nominated for Best Original Song. The score lost to Bob Fosse's All That Jazz. The song lost to "It Goes Like It Goes" from Norma Rae, a win that some critics denounced.

The song's name has been used by a number of charitable organizations wishing to evoke its message, including a children's charity similar to the Make-A-Wish Foundation, a summer camp for seriously ill children, and a horseriding camp for people with disabilities. The name's influence can also be seen from business names to artificial Christmas tree products.