"That'll Be the Day" is a song written by Buddy Holly and Jerry Allison and recorded by various artists including The Crickets and Linda Ronstadt. It was also the first song to be recorded (just as a demonstration disc) by The Quarrymen the skiffle group that subsequently became The Beatles. Although Norman Petty was given a co-writing credit on it, he was not actually involved in the composition, but only in the production of this well-known recording.

The song had its genesis in a trip to the movies by Holly, Allison and Sonny Curtis in June 1956. The John Wayne film The Searcherswas playing. Wayne's frequently-used, world-weary catchphrase, "That'll be the day." inspired the young musicians.

The version of this song that became a number-one hit on the 1957 "Best Sellers in Stores" chart in magazine was recorded eight months later, at the Norman Petty studios in Clovis, New Mexico, on February 25, 1957, and issued on the Brunswick Records label three months later. The song also went to number two on the R&B chart.

Because Holly had signed a recording contract with Decca he was contractually prohibited from re-recording any of the songs recorded during the 1956 Nashville sessions for five years, even if Decca never released them. To dodge this, producer Norman Petty credited The Crickets as the artist on this new recording of "That'll Be the Day" to shield Buddy from possible legal action. Ironically, Brunswick Records was a subsidiary of Decca Records. Once the cat was out of the bag, Decca re-signed Holly to another of its subsidiaries, Coral Records, so he ended up with two recording contracts. His group efforts would be issued by Brunswick, and his solo recordings would be on Coral.

The re-recorded version of "That'll Be the Day" was released by Brunswick Records on May 27, 1957, and is featured on the debut album by The Crickets, The "Chirping" Crickets, which was issued on November 27, 1957. The song is considered a classic in the rock and roll genre and is listed at #39 on Rolling Stone's list of The 500 Greatest Songs of All Time.

In 1958, the song was the first track ever recorded by The Quarrymen, who later became The Beatles; their rendition, intended just as a demonstration disc, was issued officially on the Beatles Anthology 1in 1995. Norman Petty sold the publishing rights to the Buddy Holly catalogue to Paul McCartney in 1979.

Linda Ronstadt covered the song on 1976's Grammy award winning Hasten Down the Wind. The single made it to number 11 on the BillboardPop Singles chart and number 27 on the Billboard Country Singles chart.

The Flamin' Groovies covered "That'll be the Day" in 1972; their rendition is on the reissue of their album Teenage Head.

Paul and Barry Ryan covered the song on their debut album Two of a Kind(Decca LP LK4878, 1967).

Overboard has a rendition on their 2008 album Castaways.