Chad Guy Bertrand le Clos, OIS (born 12 April 1992) is a South African competitive swimmer who is an Olympic, World and Commonwealth Games champion. He is the African record, Commonwealth record, and South African record holder in the short course and long course 200-metre butterfly and the short course 100-metre butterfly. He also holds African and South African records in the long course 200-metre freestyle and 100-metre butterfly, as well as the short course 100-metre freestyle. Formerly, he was a world record holder in the short course 100-metre butterfly and 200-metre butterfly.
At the 2012 Summer Olympics, he won a gold medal in the 200-metre butterfly and a silver medal in the 100-metre butterfly, as well as silver medals in the 200-metre freestyle and 100-metre butterfly at the 2016 Summer Olympics. He won five total medals at the 2010 Summer Youth Olympics. Le Clos has won the Swimming World Cup overall male winner title four times: 2011, 2013, 2014, and 2017. Across the 2010, 2014, 2018 and 2022 Commonwealth Games, he has won a total of 18 medals, including seven gold medals, four silver medals, and seven bronze medals. He has won a total of 19 medals, 12 gold medals, 5 silver medals, and 2 bronze medals, in individual events at Short Course World Championships.
At the 2014 Commonwealth Games, he tied the record set by Ian Thorpe for the most number of medals won at a single Commonwealth Games with seven medals. He became South Africa's most decorated Olympian when he won his fourth Olympic medal at the 2016 Summer Olympics. In 2017, he became the first male to win the overall title in the Swimming World Cup four times. Upon his completion of the 2018 Swimming World Cup, he won the Guinness World Record for "most gold medals won in the FINA Swimming World Cup by a male swimmer" for the 143 gold medals he won between 2009 and 2018, inclusive. In the same year, he became the most decorated Commonwealth Games swimmer, with 17 total medals, and the first man to win the Commonwealth Games title in the 200-metre butterfly three times in a row. At the 2022 Commonwealth Games, he became the third person to win 18 medals at the Commonwealth Games and tied for the title of the most decorated competitor.