Eusebius Mandyczewski (Ukrainian: Євсевій Мандичевський Ėvsevij Mandyčevśkyj, Romanian: Eusebie Mandicevschi; 18 August 1857, Molodiya – 13 August 1929, Vienna) was a Romanian musicologist, composer, conductor, and teacher. He was an author of numerous musical works and is highly regarded within Austrian, Romanian and Ukrainian music circles.
Eusebius Mandyczewski was born in the village of Molodiya (then Austria-Hungary; now Ukraine, Hlyboka Raion) on 18 August 1857. His father was a priest and his mother, Veronica, born Popovici, was the sister of Eusebiu Popovici, erudite professor of History at the University of Cernauti and the father of the Bucovinian poet Gheorghe Popovici (known under the pen name of T. Robeanu). His origin according to the father has Slavic affiliations; according to his mother the origin is Romanian. Eusebius had two brothers (Georgiy and Prof.Kostiantyn) and one sister (Kateryna). Kostiantyn was a secondary school teacher, member of the regional School Council and later Head of the Chernivtsi Library. Kateryna Mandychevs'ka was a school teacher. Georgiy was also a composer of choral music.
He finished his secondary studies at the upper school of Chernivtsi and simultaneously studied music under Sydir Vorobkevych. He began studies at the University of Chernivtsi, then moved to the Vienna Conservatory in 1875 and studied music history under Eduard Hanslick, music theory under Martin Gustav Nottebohm and Robert Fuchs. Beginning in 1879, he became a close and lifelong friend of Johannes Brahms and a prominent member of the 'Brahms circle' (who aided Brahms in teaching Gustav Jenner). Johannes Brahms supported the young composer and appointed him as curator of his estate.