Duarte da Silva Marques (born December 3, 1983, in Rio Maior) is a triathlete from Portugal. He competed at the 2008 Summer Olympics in Beijing, where he placed forty-fifth in the men's triathlon, with a time of 1:55:06.
At the peak of his career, Marques has achieved 14 top ten finishes in over fifty competitions, including his championship triumph at the 2007 ITU European Cup in Split, Croatia.