William Courtenay, 8th Earl de jure of Devon (30 October 1742 – 14 October 1788) was the eldest son of William Courtenay 7th de jure Earl of Devon, and Lady Frances Finch. He succeeded to the title of 4th Baronet Courtenay, 2nd Viscount Courtenay of Powderham Castle and 8th Earl of Devon (Created c.1553) on 16 May 1762 upon the death of his father.

Family

He married Lady Frances Clack (d. 25 March 1782) on (7 May 1762) with whom he had the following children: And one illegitimate child. The mother of this child is unknown, all that is known is the child had the surname "Vane" and she was "akin" to Sir Henry Vane the Younger who died of beheading in 1662 over one hundred years earlier.