Grant Hackett (born May 9, 1980), Australian swimmer, won the men's 1500 meters freestyle race at both the 2000 Summer Olympics in Sydney and the 2004 Summer Olympics in Athens, making him one of Australia's greatest ever distance swimmers.

Hackett was born at Southport on the Gold Coast of Queensland, and first achieved prominence at the 1997 World Championships, where he first won the 1500 meters. He also won the event at the 1998 Commonwealth Games. Since 1999 he has been unbeaten in the 1500, winning it at every major world competition, including the World Championshipsm and Pan Pacific Championships.

Over shorter distances, however, Hackett has been somewhat overshadowed by his fellow Australian Ian Thorpe. Despite this, he is a hugely popular figure in Australia. His extroverted personality is in sharp contrast with Thorpe's more reserved style. and is more in line with Australian expectations of sporting figures. His major interests outside swimming are playing the guitar and motor racing.

At 196 cm (six foot five) and 89.8 kg (198 pounds), Hackett is an imposing figure, who wins the gruelling 1500 meters race by sheer physical strength and stamina. He showed this in Sydney when he won despite having only partly recovered from illness, and again in Athens, when he survived challenges from swimmers six years his junior to hang on win the race.