János Ferencsik (18 January 1907 – 12 June 1984) was a Hungarian conductor. Ferencsik was born in Budapest; he actively played music even as a very young boy. He took violin lessons and taught himself to play the organ. He studied at the National Conservatory of Music in Budapest, where his major subjects were organ performance and composition. He joined the Budapest State Opera at the age of twenty, where he was engaged as a rehearsal coach. In this capacity he took part in the Bayreuth Festival in 1930 and 1931. In Bayreuth, he assisted Arturo Toscanini, an experience which was to be of decisive importance for the remainder of his career.