Brent Matthew Hayden (born October 21, 1983) is a Canadian retired competitive swimmer. Representing Canada for a decade, Hayden is regarded as the fastest swimmer in Canadian history. Hayden won a bronze medal in the 100 m freestyle at the 2012 Summer Olympics in London with a time of 47.80, and was world champion in the same event in 2007 with Filippo Magnini of Italy. By winning the 100 metre, Hayden became the first Canadian in 21 years to win a gold medal at the World Aquatics Championships, and was also the first Canadian to appear in the 100 metre final at the Olympics since Dick Pound at the 1960 Summer Olympics, and the first Canadian to win an Olympic medal in the 100 metre. Hayden added a further three silver and one bronze medal to his World Championship totals.
Hayden is currently the Canadian record-holder in the 200 metre and 100 metre in both the short-course and long-course. He has also held the world record in the 4×100 metre medley relay, and the 4×200 metre freestyle relay. Initially retiring after the London Olympics, Hayden returned to the pool seven years later to compete at the 2020 Summer Olympics in Tokyo.