Sunflower is the 16th studio album by the American rock band the Beach Boys, released on August 31, 1970 on Reprise Records, their first for the label. It received favorable reviews, but sold poorly, reaching number 151 on the US record charts during a four-week stay and becoming the lowest-charting Beach Boys album to that point. "Add Some Music to Your Day" was the only single that charted in the US, peaking at number 64. In the UK, the album peaked at number 29.

Working titles for the album included Reverberation, Add Some Music, and The Fading Rock Group Revival. The recording sessions began in January 1969, and, after a year-long search for a new record contract, completed in July 1970. In contrast to 20/20, the record featured a strong group presence with significant writing contributions from all band members. About four dozen songs were written for the album, and the label rejected numerous revisions of its track listing before the band presented enough formidable material deemed satisfactory for release. It includes "This Whole World", one of Brian Wilson's most complex songs, "Forever", regarded as among Dennis Wilson's finest, and "Cool, Cool Water", a song that originated from the band's Smile sessions.

Fans generally consider Sunflower to be among the Beach Boys' finest post-Pet Sounds albums. It has appeared in several critics' and listeners' polls for the best albums of all time, including Rolling Stone's 2003 list of the "500 Greatest Albums of All Time". The track "All I Wanna Do" was later cited as one of the earliest examples of dream pop and chillwave. Many Sunflower outtakes and leftover songs later appeared on subsequent Beach Boys releases, including the follow-up Surf's Up (1971) and the compilation Feel Flows (2021).