Eötvös was born in Székelyudvarhely, Transylvania, then part of Hungary, now Romania. He studied composition in Budapest and Cologne. From 1962, he composed for film in Hungary. Eötvös played regularly with the Stockhausen Ensemble between 1968 and 1976. He was a founding member of the Oeldorf Group in 1973, continuing his association until the late 1970s. From 1979 to 1991, he was musical director and conductor of the Ensemble InterContemporain (EIC). From 1985 to 1988, he was principal guest conductor of the BBC Symphony Orchestra.
