Santos Benigno Laciar (born 31 January 1959), is an Argentine former professional boxer who competed from 1976 to 1990. He is a world champion in two weight classes, having held the World Boxing Association (WBA) flyweight title twice between 1981 and 1985, and the World Boxing Council (WBC) super-flyweight title in 1987.

Laciar was born in Huinca Renancó, in the province of Córdoba, Argentina.

Laciar began his career in his hometown, on December 3 of 1976, knocking out Carlos Maliene in four rounds. After three more wins, all by knockout, he was faced with Alejandro Holguin, who held him to a ten-round draw, becoming the first boxer to face Laciar and not come out on the losing end. After three more wins, he drew once again, this time against Jose Ibiris, but in his next fight, he was able to take the Córdoba State Flyweight title away from Carlos Reyes Sosa in Villa María with a 12-round decision. He finished 1977 with four more wins, including a knockout in six in a rematch with Reyes Sosa.

In 1978 he had 13 fights, for an average of slightly more than one fight per month. Among his fights that year: a rematch with Ibiris, which ended in a ten-round decision win for Laciar, two fights versus contender Ramon Soria, which ended in a draw and in Laciar's first defeat, a 10-round decision loss, a fight with Luis Gerez, who drew with Laciar, and Laciar's Buenos Aires debut, a 10-round decision win over Angel Luis Fernandez.

1979 was another busy year for Laciar, boxing 13 times again during that year. He won 9 of those bouts. Among his fights in '79, a loss to future world Junior bantamweight champion Gustavo Ballas, who beat him in 10 on points, a rubber match with Ibris, resulting in another Laciar 10-round decision win, two decision losses to Raúl Pérez, and a 10-round decision win against top contender Federico Condori.

But early in 1980 Laciar started what would turn out to be a great decade for him. He was matched with Miguel Lanzarte on February 26 of that year for the vacant Argentinian flyweight title and won the bout by a decision in 12. After a draw in ten against Condori's brother Ruben, he won four straight bouts, and on August 30, he challenged for the South American flyweight title. In what was his first fight outside Argentina, he and South American champion Jaime Miranda battled to an 8-round no contest (a no contest is declared when circumstances beyond boxing cause the fight to be stopped) in Santiago, Chile. After one more win over Federico Condori, Miranda returned the favor by travelling to Laciar's country and this time, Laciar won the South American title with a 12-round decision win. Laciar finished the year by travelling to England, where he lost a 10-round decision to future world champion Charlie Magri.

In 1981, one day before his birthday, he beat Jose de la Cruz in Mar del Plata. He was already ranked number one by the WBA, and in March he flew to South Africa, where he beat Peter Mathebula on the 28th day of that month, by a knockout in seven rounds to become the world's flyweight champion. After the retirement of Carlos Monzón in 1977 and Victor Galindez in 1978, (Galindez died in 1980 in an auto race accident), Argentina was in need of a world champion boxer, and Laciar became a national hero instantly.

A rematch with Lanzarte, resulting in a 10-round non title decision win, followed, and then he fought at the Luna Park, where he lost his title to Luis Ibarra.