Rex Williams, English snooker player
Desmond Rex Williams (born 20 July 1933) is a retired English professional snooker and billiards player. He was the second player to make an official maximum break, achieving this in an exhibition match in December 1965. Williams won the World Professional Billiards Championship from Clark McConachy in 1968, the first time that the title had been contested since 1951. Williams retained the title in several challenge matches in the 1970s, and, after losing it to Fred Davis in 1980, regained it from 1982 to 1983.

He played a leading role in the re-establishment of the World Snooker Championship on a challenge basis in 1964, and lost twice to John Pulman, once in a single match and once in a series of matches played in South Africa. When the Championship reverted to being a knockout from 1969, he reached the semi-finals three times. In 1968 he initiated the revival of the Professional Billiards Players Association (known as the World Professional Billiards and Snooker Association from 1970). He chaired the association, barring a few weeks in 1983, until 1987, and again from 1997 to 1999.

Williams was a successful junior player in both snooker and billiards, and became a professional in 1951 at the age of 18. At the 1986 Grand Prix, aged 53, he became the oldest player to reach a ranking tournament final. He lost the match 6–10 to Jimmy White after leading 6–4. He retired from competitive snooker in 1995, having achieved his highest ranking, 6th, in 1976/77.