Ruben Wálter Paz Márquez (born August 8, 1959 in Artigas) was a Uruguayan football midfield player, who retired in 2006 at the age of 47. Paz played at two FIFA World Cups for Uruguay and was also South American Footballer of the Year in 1988. He's currently Peñarol's assistant coach.

Ruben Paz began his career at the age of 17 when he joined the Club Atlético Peñarol Montevideo in 1977. He played in Peñarol until 1981, where he obtained important achievements, winning 3 consecutive championships Uruguayans (1978-79-80).

In 1982 he emigrated to the Brazilian League, specifically the Rio Grande do Sul team Internacional where he won three consecutive championships Gauchos (1982-83-84).

In 1986 makes the leap to Europe, specifically to Matra Racing Paris (now the Racing Club de France) of the Ligue 1 of the French Football League, where he highlighted alongside his compatriot Enzo Francescoli.

The following year he was transferred to Racing Club de Avellaneda in the Argentine league, where he becomes the team leader and an idol for the fans of the squad that conquered the South American Super Cup and Super Cup Inter in 1988. He was one of the few players in the Argentinian football was respected by all supporters. That same year he was awarded the trophy as the Best Player of South America.