Balduin Hoyoul (1547-8 - 26 November 1594) was a Renaissance composer of the Franco-Flemish school.
Hoyoul was born in Liège. From the age of 13 he was a discant singer at the Court in Stuttgart under Ludwig Daser. Between 1563 and 1564 he was a pupil of Lassus in Munich. In 1589 Hoyoul took over from his father-in-law as Hofkapellmeister in Stuttgart. In 1593 he applied, unsuccessfully, for the more prestigious court post at Dresden. He died of the plague in Stuttgart in 1594, and was succeeded in Stuttgart by another pupil of Lassus, Leonhard Lechner.