Mario Castelnuovo-Tedesco (April 3, 1895 – March 16, 1968) was an Italian composer. He was known as one of the foremost guitar composers in the twentieth century with almost one hundred compositions for that instrument. In 1939 he migrated to the United States and became a film composer for MGM Studios for some 200 Hollywood movies for the next fifteen years. He also wrote concertos for such soloists as Jascha Heifetz and Gregor Piatigorsky.