Sydir Vorobkevych (Ukrainian: Сидір Іванович Воробкевич, Romanian: Isidor Vorobchievici) (1836–1903) was a Ukrainian composer, writer, Eastern Orthodox priest, teacher, artist, and newspaper editor of Bukovina. He used following pen-names: Danylo Mlaka, Demko Makoviychuk, Morozenko, Semen Khrin, Isydor Vorobkevych, S.Volokh, and others.
Sydir Vorobkevych was born 18 May 1836 in Chernivtsi to a family of Orthodox priests and theologians. His brother was Ukrainian poet Hryhoriy Vorobkevych.
Vorobkevych's great-grandfather, Skalsky Mlaka de Orobko, ran away from Lithuania, and his grandfather changed his name from Orobko to Vorobkevych. He later used part of the former name as part of his pseudonym Danilo Mlaka. His mother died early in 1840, and his father Ivan worked in the Chernivtsi Lyceum as a professor of religion and philosophy. His father died in 1845 and Sydir along with his brother Hryhoriy were left orphans. They went to live with their grandfather, Mykhailo Vorobkevych, the Protopope of Kitsman.
In his family the young Vorobkevyches learned Ukrainian folklore and history. Soon Sydir enrolled in the Chernivtsi Lyceum and later the Theology Seminary in Chernivtsi, graduating in 1861. He began to compose his first verses as a student. After seminary, Vorobkevych began an internship as a priest in the neighboring villages. Later he enrolled in the musical courses of the Vienna Conservatory under professor Franz Krenn. Since 1867, Vorobkevych had been a singing instructor in the Chernivtsi Theology Seminary and Lyceum, and in 1868 he took a test for certified singing instructor and choir regent. In 1875, he became a singing instructor at the Theological Department of the Chernivtsi University. During that time, he already worked as a composer creating his own songs, psalms, choir works, operettas, and others.