In August 1997, Williamson moved to Everton in an exchange for David Unsworth and £1 million as Howard Kendall sought to add creativity and strength to the Everton midfield and Harry Redknapp sought a left-sided centre-half to fill a gap created by a long-term injury to captain Julian Dicks. He made his debut for Everton in a 2–1 victory over West Ham on 23 August 1997 and went on to make a total of 17 appearances for Everton in the 1997/98 season. He picked up a foot injury against Wimbledon on 13 December 1997 and the injury, which required surgery, and subsequent complications led him to miss the rest of the 1997/98 season and the two following seasons 1998–1999 and 1999–2000.