Duncan Seth Free OAM (born 25 May 1973) is a retired Australian rower and Olympic gold medallist.

[2] He was the Queensland state representative sculler picked to race the President's Cup at the Australian Rowing Championships eight times from 1996 to 2004.

[3] Free won Diamond Sculls event at the 2001 Henley Royal Regatta racing for the Surfer's Paradise Rowing Club.

[4] Duncan and his brother Marcus were paired in the men's double scull at two world championships (1997 and 1998) coached by Reg.

After the Athens Games, Duncan took a year off before switching to sweep rowing and establishing a partnership with gold medallist Drew Ginn in the coxless pair.