Foster Neil "Fos" Williams AM (21 February 1922 – 1 September 2001) was a leading Australian rules footballer who played for and coached the Port Adelaide and West Adelaide Football Clubs and coached South Adelaide in the South Australian National Football League (SANFL) in a career spanning 1946–1978.
He also played 34 interstate games for South Australia, captaining the team from 1954–1958 and he coached the team in 45 games from 1955–1969.