Surf's Up is the 17th studio album by American rock band the Beach Boys, released on August 30, 1971 on Brother/Reprise. It received largely favorable reviews and reached number 29 on the U.S. record charts, becoming their highest-charting LP of new music in the U.S. since 1967. In the UK, Surf's Up peaked at number 15, continuing a string of top 40 records that had not abated since 1965.

The album's title and cover artwork (a painting based on the early 20th-century sculpture "End of the Trail") are an ironic, self-aware nod to the band's early surfing image. Originally titled Landlocked, the album took its name from the closing track "Surf's Up", a song originally intended for the group's unfinished album Smile. Most of Surf's Up was recorded from January to July 1971. In contrast to the previous LP Sunflower, Brian Wilson was not especially active in the production, which resulted in thinner vocal arrangements.

Lyrically, Surf's Up addresses environmental, social, and health concerns more than the group's previous releases. This was at the behest of newly recruited co-manager Jack Rieley, who strove to revamp the group's image and restore their public reputation following the dismal reception to their recent albums and tours. His initiatives included a promotional campaign with the tagline "it's now safe to listen to the Beach Boys" and the appointment of Carl Wilson as the band's official leader. The record also included Carl's first major song contributions: "Long Promised Road" and "Feel Flows".

Two singles were issued in the U.S.: "Long Promised Road" and "Surf's Up". Only the former charted, when it was reissued with the B-side "'Til I Die" later in the year, peaking at number 89. In 1993, Surf's Up was ranked number 46 in NME's list of the "Top 100 Albums" in history. In 2000, it ranked number 230 in Colin Larkin's All Time Top 1000 Albums. Session highlights, outtakes, and alternate mixes from the album were collected for the 2021 compilation Feel Flows.