Mark Melville Williams (born 21 August 1958) is a former Australian rules football player and coach. As a player, Williams represented West Adelaide and Port Adelaide in the South Australian National Football League (SANFL), as well as Collingwood and Brisbane Bears in the Australian Football League (AFL), from the 1970s to the 1990s.

One of several successful father-son combinations in Australian rules football, Williams became a successful coach after finishing his playing career, leading Port Adelaide to their first AFL premiership in 2004.

In early December 2020, Williams was appointed the new head of development at Melbourne Football Club in an assistant coaching role, replacing the former head of development Matthew Egan and working with senior coach Simon Goodwin. Williams also played a key off-field role in the club's 2021 premiership victory by being part of the club's coaching panel.

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