Adam Charles Clayton (born 13 March 1960) is an English-Irish musician who is the bass guitarist of the rock band U2. Born in Oxfordshire, England, he lived in County Dublin, Ireland after his family moved to Malahide in 1965, when he was five years old. Clayton attended Mount Temple Comprehensive School, where he met schoolmates with whom he co-founded U2 in 1976. A member of the band since its inception, he has recorded 15 studio albums with U2.

Clayton's bass playing style is noted for its "harmonic syncopation", giving the music a driving rhythm. He is well known for his bass playing on songs such as "Gloria", "New Year's Day", "Bullet the Blue Sky", "With or Without You", "Mysterious Ways", "Vertigo", "Get On Your Boots", and "Magnificent". He has worked on several solo projects throughout his career, such as his work with fellow band member Larry Mullen Jr. on the 1996 version of the "Theme from Mission: Impossible". As a member of U2, Clayton has received 22 Grammy Awards and was inducted into the Rock and Roll Hall of Fame in 2005.