Justus D. Williams (born 25 May 1998) is an American chess player who holds the title of International Master (IM).

When Williams was 12 years old, he became the youngest African American to earn the US Chess Federation (USCF) title of National Master (NM), surpassing Kassa Korley and since surpassed by several players, including current record-holder Brewington Hardaway.

Williams was featured as the star player of his junior high school chess team in the 2012 documentary Brooklyn Castle.

Williams attended Webster University in St. Louis, where he played on the chess team on a full scholarship with middle school teammate James Black Jr. and fellow New York City area player Joshua Colas, both of whom also appeared in the Brooklyn Castle film.

He had earned all three of his IM norms by 2017 and clinched the title by reaching the rating threshold of 2400 four years later.