Camelot is a musical with music by Frederick Loewe and lyrics and a book by Alan Jay Lerner. It is based on the legend of King Arthur as adapted from the 1958 novel The Once and Future King by T. H. White.

The original 1960 production, directed by Moss Hart with orchestrations by Robert Russell Bennett and Philip J. Lang, ran on Broadway for 873 performances, winning four Tony Awards. It starred Richard Burton as Arthur, Julie Andrews as Guenevere, and Robert Goulet as Lancelot.

It spawned several notable productions including four Broadway revivals and a 1967 film adaptation. The 2023 Broadway revival features a revised book by Aaron Sorkin.

The musical has become associated with the Presidency of John F. Kennedy, which is sometimes called the "Camelot Era", because of an interview with Jackie Kennedy in which she compared her husband's presidency to King Arthur's reign, specifically mentioning his fondness for the musical and particularly the closing lyrics of the eponymous final song.

In 1959, Alan Jay Lerner and Moss Hart decided to adapt T. H. White's The Once and Future King as their next project. As discussed in Lerner's 1978 book, The Street Where I Live, Frederick Loewe, who initially had no interest in the project, agreed to write music, with the understanding that if things went badly, it would be his last score. After the tremendous success of My Fair Lady, expectations were high for a new Lerner and Loewe musical. However, the show's production met several obstacles. Lerner's wife left him during the writing process, causing him to seek medical attention and delaying the production.

When Camelot began rehearsals, it still needed considerable work. However, the producers were able to secure a strong cast, including Julie Andrews, Richard Burton, and Roddy McDowall, as well as Robert Goulet in his first Broadway role. John Cullum also made his Broadway debut as Sir Dinadan; Bruce Yarnell was Sir Lionel. Cullum later replaced McDowall, and William Squire replaced Burton. Other replacements included Patricia Bredin (as of April 16, 1962), Kathryn Grayson (as of October 23, 1962) and Janet Pavek (as of July 9, 1962) for Andrews.

The show premiered in Toronto, at the O'Keefe Centre on October 1, 1960. It overran drastically — it was supposed to last two hours forty minutes, and instead clocked in at four and a half hours. The curtain came down at twenty minutes to one in the morning; Lerner later noted that "Only Tristan and Isolde equaled it as a bladder endurance contest." Noël Coward is supposed to have remarked that the show was "longer than the Götterdämmerung ... and not nearly as funny!" In spite of this, the morning papers gave generally positive reviews, but hinted that the show needed much work, i.e., drastic editing, in order to succeed. Soon afterwards, Lerner was hospitalized for three weeks with a bleeding ulcer. Soon after he was discharged, Hart suffered his second heart attack, and Lerner stepped in as temporary director for the rest of the out-of-town run. Camelot then moved to Boston, edited, but still running well over the intended length. The production team tried to find another director, even phoning José Ferrer, who could not undertake the job. Lerner and Loewe disagreed on how to proceed with the show, as Loewe did not want to make any major changes without Hart's guidance. Lerner wrote: "God knows what would have happened had it not been for Richard Burton." Accepting cuts and changes, he radiated a "faith and geniality" and calmed the fears of the cast. Guenevere's song "Before I Gaze at You Again" was given to Andrews at the last minute before the first New York preview, which provoked her famous quote, "Of course, darling, but do try to get it to me the night before." After the show opened on Broadway, Hart was released from the hospital, and he and Lerner began cutting the play even further. Two songs, "Then You May Take Me To the Fair" and "Fie on Goodness," were cut a few months into the run (though they remain on the cast album, and the former featured in the 1967 film).

The New York critics' reviews of the original production were mixed. However, Ed Sullivan approached Lerner and Loewe to create a segment for his television variety program, celebrating the fifth anniversary of My Fair Lady. They decided to do very little from their previous hit and instead to perform four highlights from Camelot. The show stimulated ticket sales, and Camelot achieved an unprecedented advance sale of three and a half million dollars. Robert Goulet received favorable reviews, most notably for his rendition of the show-stopping romantic ballad "If Ever I Would Leave You", which became his signature song.