Gabriel Markus (born 31 March 1970) is a former professional tennis player from Argentina.

[1] The right-handed player made the fourth round of the US Open in 1991, the furthest he would reach in a Grand Slam.

At the 1992 French Open he memorably pushed second seed Stefan Edberg to five sets in the second round, but was unable to register a win.

[2] Markus won France's Phillips Open in 1992, his only title win on the ATP World Tour.

He defeated Denmark's Morten Christensen in their 1992 World Group encounter and beat both Uruguayan singles players when Argentina faced Uruguay in 1994.