Ruben Wálter Paz Márquez (born 8 August 1959) is a Uruguayan former professional footballer who played as a midfielder.

Paz played at two FIFA World Cups for Uruguay and was also South American Footballer of the Year in 1988.

Ruben Paz began his career at the age of 17 when he joined the Club Atlético Peñarol Montevideo in 1977.

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 Interamericana Super Cup [es] in 1988.

During the 1989–90 season he transferred to Genoa in the Serie A of the Italian Football League, coinciding with two compatriots, José Perdomo and Carlos Aguilera.