William Legge, 2nd Earl of Dartmouth, PC, FRS (20 June 1731 – 15 July 1801), styled as Viscount Lewisham from 1732 to 1750, was a British statesman who served as Secretary of State for the Colonies from 1772 to 1775, during the initial stages of the American Revolution.

It was Lord Dartmouth who, in 1764, at the suggestion of Thomas Haweis, recommended John Newton, the former slave trader and author of "Amazing Grace", to Edmund Keene, the Bishop of Chester.

Lord Dartmouth's political career began with the presidency of the Board of Trade and Foreign Plantations from 1765-1766.

He received many letters from North Carolina royal governor Josiah Martin in the summer of 1775 communicating preparations the Loyalist government was making against Patriot militia units and events of the revolution.

Lord Dartmouth was a large donor to and the leading trustee for the English trust that would finance the establishment of the Moor's Charity School, in Lebanon, Connecticut, by Eleazar Wheelock to educate and convert the Indians.

The famous painter Sir Joshua Reynolds painted the Earl's portrait and donated it to the hospital.

[6] Lord Dartmouth married Frances Catherine Nicholl, daughter of Sir Charles Gounter Nicoll, on 11 January 1755.