Alan Charles Jardine (born September 3, 1942) is an American musician who co-founded the Beach Boys. He is best known as the band's rhythm guitarist, background vocalist, and for occasionally singing lead vocals on singles such as number-one hit "Help Me, Rhonda" (1965), "Then I Kissed Her" (1965), "Cottonfields" (1970), and a cover of the Del-Vikings' "Come Go with Me" (1981). His song "Lady Lynda" was also a UK top 10 hit for the group in 1979. Other Beach Boys songs that feature Jardine on lead include "I Know There's an Answer" (1966), "Vegetables" (1967), a cover of Buddy Holly's "Peggy Sue" (1978), and "From There to Back Again" (2012).

Following the death of fellow band member Carl Wilson in 1998, Jardine quit the Beach Boys and has since performed as a solo artist, rejoining the band only for their 50th anniversary tour in 2012. Jardine has also toured solo in various configurations and toured alongside longtime friend and fellow Beach Boys founder Brian Wilson, first as a guest at select dates in 2006 and 2007 and again after the collapse of the reunion tour in late 2012. He has released one solo studio album, A Postcard from California (2010), and one solo EP, Islands in the Sun (2025). Jardine was inducted into the Rock and Roll Hall of Fame as a member of the Beach Boys in 1988.