Joaquim Carvalho Cruz (born March 12, 1963) is a former Brazilian athlete, winner of the 800 m at the 1984 Summer Olympics.

Cruz was born in Taguatinga , near Brasilia, as the son of a steel worker. He began running as 13-year-old, and soon showed to have talent. After setting a junior world record in 1981, he received a scholarship for the University of Oregon in 1983. The move immediately paid off, and Cruz won the NCAA championships over 800 m that same year. He also competed in the inaugural World Championships, winning the bronze.

The following year, the Olympic Games were held in Los Angeles, and Cruz was considered to be one of the favourites, along with world record holder Sebastian Coe of Britain. In the final turn, Cruz start a sprint from third place and took the lead, never losing it. He crossed the line in 1:43.00, a new Olympic Record, making him the first, and as of 2004 only, Brazilian to become Olympic champion in a track and field event.

Due to a cold, Cruz did not start in the semi-finals of the Olympic 1500 m, which caused quite a stir among the Brazilians, who thought he didn't want to represent his country in an event in which his chances of winning were smaller.

Four years later, at the 1988 Summer Olympics, Cruz appeared to be on his way to retain his Olympic 800 m title when he was passed by Kenyan runner Paul Ereng, leaving Cruz with the silver medal. Troubled by Achilles' tendon injuries, Cruz was never again able to reach the international top level.