Domingos Silva Castro (born 22 November 1963 in Fermentões-Guimarães) is a former long-distance runner from Portugal, who was one of the leading athletes in the longer events during the late 1980s, early 1990s.

At the 1988 Olympic Games, he ran the 5,000m and, as the race unfolded, Kenyan athlete John Ngugi made a substantial leading break.

Castro made a brave attempt to chase him and for several laps held on to the silver medal position.

In the last lap however, Castro's form started to fade, and in the last 30 metres, West German Dieter Baumann and East German Hansjörg Kunze sprinted past him, taking silver and bronze respectively, robbing a distraught Castro of a reward for his brave run.

The two of them represented their native country at the 1988 (Seoul, South Korea) and 1992 Summer Olympics (Barcelona, Spain).