Clifford Williams is an English musician, best known as the bassist and backing vocalist of the Australian hard rock band AC/DC. He started his professional music career in 1967 and had previously been in the English groups Home and Bandit. His first studio album with AC/DC was Powerage in 1978. Williams was inducted into the American Rock and Roll Hall of Fame as a member of AC/DC in 2003. Williams announced his retirement from AC/DC in 2016, but returned for their 2020 comeback album Power Up along with band mates Brian Johnson and Phil Rudd. His side projects include benefit concerts.

AC/DC are an Australian rock band formed in 1973. They were founded by brothers Malcolm Young on rhythm guitar and Angus Young on lead guitar. Their current line-up comprises Angus, bass guitarist Cliff Williams, drummer Phil Rudd, lead vocalist Brian Johnson and rhythm guitarist Stevie Young, nephew of Angus and Malcolm. Their music has been variously described as hard rock, blues rock and heavy metal, but the band calls it simply "rock and roll". They are cited as a formative influence on the new wave of British heavy metal bands, such as Def Leppard and Saxon. AC/DC were inducted into the Rock and Roll Hall of Fame in 2003.