Hon. William Augustus Montagu (1752–1776) was a British politician who sat in the House of Commons from 1774 to 1776. Montagu was the second surviving son of John Montagu, 4th Earl of Sandwich and his wife Dorothy (in some sources Judith), daughter of Charles Fane, 1st Viscount Fane, and was baptized on 12 February 1752. He was educated at Eton College in 1759 and was admitted at Trinity College, Cambridge on 16 November 1768. He was also admitted at Lincolns Inn on 8 December 1768. It was said of Montagu that he possessed great talents, and by good education had every opportunity of cultivating them…. but [was ruined by] dissipated company, habits of extravagance and total neglect of his health and constitution.