Geoffrey Andrew Huegill (born 4 March 1979) is an Australian former butterfly swimmer who won silver in the 4 × 100 metre medley relay and bronze in the 100 metre butterfly at the 2000 Summer Olympics. He held the long course world record in the 50 metre butterfly from 2000 to 2003.
Geoff was born to an Australian father and a Thai mother in 1979. He is the uncle of Australian rugby league player Chris McQueen.
On 12 November 2008, Huegill announced his comeback to competitive swimming. Having had major battles with his weight since quitting the sport following the 2004 Athens Olympics. He said he had lost more than 40 kilograms (coming from 138 kg) for his comeback and would train for the 50 and 100 butterfly with the aim of competing at the 2010 Delhi Commonwealth Games. He sparked attention of the Australian sports media by qualifying for the finals in the 50 and 100 metre butterfly at the 2009 Telstra Australian Championships (being interviewed after every swim). He built more momentum in August 2009 at the Australian Short Course Championships, capturing his first national medal in 5 years.