Simon Boyleau (fl. 1544–1586) was a French composer of the Renaissance, active in northern Italy. A prolific composer of madrigals as well as sacred music, he was closely connected with the court of Marguerite of Savoy. He was also the earliest documented choirmaster at the church of Santa Maria presso San Celso in Milan.

Nothing is known of his early life. A French origin is indicated by three bits of evidence: his name, a dedication he left in a manuscript book of madrigals, in which he said he was of French nationality, and a comment by the Paduan publisher of his 1546 collection of madrigals for four voices that he was French. During this period many musicians from France and the Low Countries came to Italy after receiving their early musical training in the north; employment and patronage prospects were greater in Italy throughout most of the 16th century.

Although the exact events are not documented, scholars have inferred that Boyleau probably spent his first Italian years in Venice, due to musical influences seen in his work as well as their publication history. In 1551 he became maestro di cappella (choirmaster) at Milan Cathedral, his earliest documented post; he held this position until 1557, at which time he was replaced by Hoste da Reggio. Boyleau's next position was as maestro di cappella at the church of Santa Maria presso San Celso, also in Milan; he was the first documented maestro di cappella at this institution, and he stayed there until around 1569. In 1572 Milan Cathedral hired him again, first as assistant to Vincenzo Ruffo, and then as maestro di cappella, the job he had left (or been dismissed from) fifteen years before. The Cathedral dismissed him again in 1577.