Carlos Rivas (born Oscar Weber) was an American actor, best remembered as Lun Tha in The King and I (1956), Dirty Bob in True Grit (1969), and Hernandez in Topaz (1969). Carlos Rivas was discovered in a bar in Mexico. He began his career in Mexican and Argentinian westerns, though his Argentinian films were actually filmed in Mexico.

His American debut was in The King and I (1956) opposite Rita Moreno. After this career highlight, he was quickly reduced to supporting roles. That same year of 1956 he appeared as Johnny Bravo in the TV western Cheyenne in the episode titled "Johnny Bravo." Rivas had co-starring roles in two science fiction films, The Beast of Hollow Mountain (1956) and The Black Scorpion (1957). Rivas played Chingachgook in The Deerslayer (1957) with Lex Barker, Forrest Tucker, and Rita Moreno.

In 1970, Rivas joined Ricardo Montalban, Henry Darrow, and other Latino actors in co-founding the Nosotros ("We") Foundation, a Los Angeles based organization devoted to improving the way Hispanics are depicted in entertainment and advocating for Latinos in the movie and television industry.