Earl of Mount Edgcumbe is a title in the Peerage of Great Britain. It was created in 1789 for George Edgcumbe, 3rd Baron Edgcumbe. This branch of the Edgcumbe family descends from Sir Piers Edgcumbe of Cotehele in Cornwall, who acquired an estate near Plymouth through marriage in the early 16th century, which was later re-named "Mount Edgcumbe". His descendant Richard Edgcumbe was a prominent politician and served as Paymaster-General of Ireland and as Chancellor of the Duchy of Lancaster. In 1742, he was created Baron Edgcumbe, of Mount Edgcumbe in the County of Devon, in the Peerage of Great Britain. Richard Edgcumbe was succeeded by his eldest son, the second Baron. He represented Plympton Erle, Lostwithiel and Penrhyn in the House of Commons and served as Lord-Lieutenant of Cornwall. On his death, the title passed to his younger brother, the third Baron. He was an Admiral of the Blue and also held political office as Treasurer of the Household and as Captain of the Honourable Band of Gentlemen Pensioners. In 1781, he was created Viscount Mount Edgcumbe and Valletort and in 1789 he was further honoured when he was made Earl of Mount Edgcumbe. Both titles are in the Peerage of Great Britain.

William Henry Edgcumbe, 4th Earl of Mount Edgcumbe, GCVO, PC, DL, styled Viscount Valletort between 1839 and 1861, was a British courtier, Conservative politician, and Volunteer officer.