Ernst Kozub (January 24, 1924 – December 27, 1971) was a German tenor and opera singer. Kozub was born in Duisburg, Germany. Though his early death prevented him from fully realising his promise, he stands out as one of the notable heldentenor voices of the 1960s. He is best known for his Wagnerian roles, including Erik in Der fliegende Holländer (which he recorded with Theo Adam and Anja Silja in 1968). Because of the quality of his voice, John Culshaw cast him as Siegfried in the Decca recording of Der Ring des Nibelungen, but his ailing health (kept as a secret by him at that time), which prevented him mastering the role within the short period of time given him by Decca led to his replacement at the last minute by Wolfgang Windgassen.