Patrick Michael Rafter (born 28 December 1972) is an Australian former world No. 1 tennis player. He reached the top Association of Tennis Professionals (ATP) singles ranking on 26 July 1999. His career highlights include consecutive US Open titles in 1997 and 1998, consecutive runner-up appearances at Wimbledon in 200 and 2001, winning the 1999 Australian Open men's doubles tournament alongside Jonas Bjorkman, and winning two singles and two doubles ATP Masters titles.

He became the first man in the Open Era to win Canada Masters, Cincinnati Masters and the US Open in the same year, which he achieved in 1998; this achievement has been dubbed the American Summer Slam. To date, only two players have followed this feat: Andy Roddick in 2003, and Rafael Nadal in 2013. Rafter is the third man in the Open Era to reach semifinals or better of every Grand Slam tournament in both singles and doubles, after Rod Laver and Stefan Edberg, and remains the last man to date to accomplish this. Rafter is also the only player to remain undefeated against Roger Federer with at least three meetings, though the meetings took place early in Federer's career. He is also the only player with a winning record over the Swiss on all the three main surfaces: hard clay and grass.