Mark Williams may refer to:

• Mark Williams (writer) (born 1951), academic, writer, critic, poet
• Mark Williams (singer) (born 1954), New Zealand singer
  • Mark Williams (album)
• Mark Williams (actor) (born 1959), British actor and comedian
• Mark Williams (organist) (born 1978), Informator Choristarum at Magdalen College, Oxford
• Mark Williams (radio host), American journalist and radio personality
• Mark "Slave" Williams, hip hop MC, television presenter
• Mark Williams (game designer), original artist at Hero Games
• Mark Williams (Holby City), fictional character in Holby City
• Mark Williams (filmmaker), American producer, director and writer
• Mark Williams (music producer), American music producer and songwriter

• Mark Williams (Australian footballer, born 1957), with North Melbourne and Footscray
• Mark Williams (Australian footballer, born 1958), with Port Adelaide, Brisbane, Collingwood, former coach of Port Adelaide
• Mark Williams (Australian footballer, born 1964), with Carlton and Footscray, former coach of Sandringham
• Mark Williams (Australian footballer, born 1983), with Hawthorn and Essendon
• Mark Williams (American football) (born 1971), American football player
• Mark Williams (South African footballer) (born 1966), South African former international footballer
• Mark Williams (footballer, born 1970), Northern Ireland former international footballer
• Mark Williams (footballer, born 1978), English footballer for Rochdale and Rotherham United
• Mark Williams (footballer, born 1981), English footballer who played as a midfielder
• Mark Williams (Scottish footballer) (born 1995), Scottish footballer

• Mark Williams (baseball) (born 1953), American former Major League Baseball player
• Mark Williams (cricketer, born 1955), English cricketer
• Mark Williams (rugby union) (born 1961), rugby player for the U.S. national rugby team
• Mark Williams (snooker player) (born 1975), Welsh professional snooker player
• Mark Williams (volleyball) (born 1979), Australian volleyball player
• Mark Williams (bowls), Welsh former world bowls champion
• Mark Williams (basketball) (born 2001), American basketball player

• Mark Williams (Colorado politician) (born 1962)
• Mark Williams (politician) (born 1966), British Member of Parliament and Welsh Liberal Democrat leader
• Mark W. Williams (1925–2013), US Army Ranger and participant in D-Day
• Mark London Williams (born 1959), American author and journalist
• Mark T. Williams (born 1963), educator, author and risk management expert
• J. Mark G. Williams, academic and author specializing in depression and suicide
• Mark Williams (engineer), British engineer

• Mark Williams Company, a small software company that created Coherent
• Marc Williams (born 1988), Welsh footballer
• Marcus Williams (disambiguation)