William Derek Bevan, (born September 3, 1947 in Clydach, Wales) is a Welsh international rugby union referee. Bevan refereed his first international match on April 22, 1984, the 1983–84 FIRA Trophy match between Italy and Romania. His final international appearance was in the 2000 Six Nations game between Ireland and Italy. Later that year, he was awarded an MBE in the Queen's birthday honours. He held the Welsh record for number of international matches refereed until 2013, when Nigel Owens surpassed his total of 44 international games.