Roger Federer (born 8 August 1981) is a Swiss professional tennis player who held the ATP number one position for a record 237 consecutive weeks. Federer has won a male record 16 Grand Slam singles titles, holding at least one Grand Slam title every single week from Wimbledon 2003 until the Australian Open in 2011. He is one of seven male players to capture the career Grand Slam and one of three (with Andre Agassi and Rafael Nadal) to do so on three different surfaces (clay, grass and hard courts). Many sports analysts, tennis critics, former and current players consider Federer to be the greatest tennis player of all time.

Federer has appeared in an unprecedented 22 career Grand Slam finals, of which 10 were consecutive appearances, and appeared in 18 of 19 finals over the four and a half years from the 2005 Wimbledon Championships through the 2010 Australian Open, excluding the 2008 Australian Open. He holds the record of reaching the semi-finals or better of 23 consecutive Grand Slam tournaments over five and a half years from the 2004 Wimbledon Championships through the 2010 Australian Open. In the 2011 Australian Open he reached his 27th consecutive quarter-finals in the grand slam tournaments, equalling the record set by Jimmy Connors.

Federer has won a record five ATP World Tour Finals (shared with Ivan Lendl and Pete Sampras) and 17 ATP Masters Series tournaments. He also won the Olympic gold medal in doubles with his compatriot Stanislas Wawrinka at the 2008 Summer Olympic Games. For the past eight years (2003–2010) he has been in the top two in the year-end rankings.

As a result of Federer's successes in tennis, he was named the Laureus World Sportsman of the Year for a record four consecutive years (2005–2008). He is often referred to as The Federer Express or abbreviated to Fed Express, the Swiss Maestro or simply Maestro.