Mario Castañeda is a Mexican voice actor who dubbed the speaking voice of Gary in Los Muppets, the Latin American dub of The Muppets. He also served as voice director (except for his own dialogue, directed by Raúl Aldana). Previously, he dubbed Quentin Tarantino in Los Muppets y el Mago de Oz (The Muppets' Wizard of Oz) and Billy Ray Cyrus in the first Studio DC: Almost Live special.

Often dubbing leading men, Castañeda is the primary Spanish voice of Bruce Willis and Jim Carrey and dubbed Mark Ruffalo as Bruce Banner in The Avengers movies, Mel Gibson in Hamlet, Tom Hanks in Angels and Demons, and Christoph Waltz in Inglorious Basterds. For TV, he dubbed Billy Ray Cyrus on Hannah Montana, Martin Freeman on Sherlock, Philip Michael Thomas on Miami Vice, and Robert Duncan McNeil on Star Trek Voyager. He was the voice of Goku in the Dragonball franchise, Iron Man in several animated projects, and Zapp Brannigan on Futurama.