John Clayton Mayer (pronounced /ˈmeɪ.ər/ MAY-ər; born October 16, 1977) is an American musician. Originally from Connecticut, he attended Berklee College of Music before moving to Atlanta, Georgia in 1997, where he refined his skills and gained a following. His first two studio albums, Room for Squares and Heavier Things, did well commercially, achieving multi-platinum status. In 2003, he won a Best Male Pop Vocal Performance Grammy Award for "Your Body Is a Wonderland".

Mayer began his career performing mainly acoustic rock, but gradually began a transition towards the blues genre in 2005 by collaborating with renowned blues artists such as B. B. King, Buddy Guy, and Eric Clapton, and by forming the John Mayer Trio. The blues influence can be heard on his album Continuum, released in September 2006. At the 49th Annual Grammy Awards in 2007 Mayer won Best Pop Vocal Album for Continuum and Best Male Pop Vocal Performance for "Waiting on the World to Change". Mayer's career pursuits have extended to stand-up comedy, design, and writing; he has written pieces for magazines, most notably for Esquire. He is also involved in philanthropic activities through his "Back to You" fund and his concern over global warming.

John Mayer was born in Bridgeport, Connecticut to Margaret, an English teacher, and Richard, a high school principal. He grew up in nearby Fairfield, the second of three children. There, he became friends with future tennis star James Blake. Mayer attended the former Fairfield High School, although he was enrolled in the Center for Global Studies at Brien McMahon High School in Norwalk for his junior year. (Then known as the Center for Japanese Studies Abroad, it is a magnet program for students wanting to learn Japanese..) During an appearance on Late Night with Conan O'Brien, he said that he had played the clarinet for a while in middle school, with minor success. After watching Michael J. Fox's guitar performance as Marty McFly in Back to the Future, he became fascinated with the instrument. Subsequently, when Mayer was 13, his father rented one for him.