William Fox may refer to:

William Speed Lane Fox-Pitt (born 2 January 1969, Hampstead), known as William Fox-Pitt, is an English equestrian. He has had notable successes at the Burghley, Badminton, Blenheim and Bramham Horse Trials. He first won the British Open Championships at Gatcombe Park in 1995 and his career highlights include an Olympic team Silver Medal at the Summer Olympic Games at Athens in 2004 and a Team Gold Medal and Individual Silver medal at the World Equestrian Games at Kentucky in 2010. In 2011 he became the first rider to win five different four-star events, having won the Burghley Horse Trials six times (1994, 2002, 2005, 2007, 2008 and 2011) with single victories at each of the Badminton Horse Trials (2004), Rolex Kentucky Three Day (2010), Luhmühlen Horse Trials (2008), and the Stars of Pau (2011).

Educated at Eton and the University of London, Fox-Pitt began riding at age four, and started eventing at age 15. He was born into an equestrian family, with both parents having ridden around Badminton and Burghley and his siblings having been very successful as well. He holds the record for the most wins (six) at the Burghley Horse Trials; William's victories coming in 1994, 2002, 2005, 2007, 2008 and 2011. Additional major wins have been at the Badminton Horse Trials in 2004, at Gatcombe Park in 1995, 2000, 2003 and 2005, and team golds in European Championships in 1995, 1997, 2001, 2003, 2005 and 2009. He also represented Great Britain at the Atlanta, Athens and Beijing Olympics, winning team silver in Athens and team bronze in Beijing. As of 2006, he was ranked the leading rider in Britain for the sixth year running and 2nd in the world. William is married to Channel 4 Racing presenter Alice Plunkett. They have two sons, Oliver who was born in August 2005 and Thomas, born 15 November 2006. William is a regular columnist in the weekly equestrian magazine, Horse & Hound.