English composer. Probably the son of William Cornysh 'senior', he entered royal service in 1492 and was a Gentleman of the Chapel Royal from 1496, being Master of the Children there from 1509 until his death. In 1504 he was imprisoned on account of a political pamphlet, but soon returned to favor. He wrote music for court pageants, one of which was performed at the Field of the Cloth of Gold, and a number of secular songs preserved in the Henry VIII manuscript. The sacred music previously attributed to him was almost certainly the work of William Cornysh 'senior'.