Sir William Parsons (1745/6–1817) was an English composer and musician who was Master of the King's Musick under George III between 1786 and 1817.
Originally a chorister at Westminster Abbey as a pupil of Benjamin Cooke,[1]: 55 he developed a reputation as a fine tenor, but was passed over for another musician at the Royal Opera House, Covent Garden and thus went to Europe to seek employment.
[2] Returning to England, he was an assistant director at the George Frideric Handel commemorations in Westminster Abbey and the Pantheon in 1784, and composed a number of anthems for royal usage.
[2] He was an assistant director of the festival with many other prominent English composers at the time, such as Thomas Sanders Dupuis, Samuel Arnold, and his teacher, Benjamin Cooke.
[3] He was knighted by the Lord Lieutenant of Ireland, John Jeffreys Pratt, second Earl Camden in 1795, thus becoming the first British musician honoured with a knighthood.