Robert Darcy, 4th Earl of Holderness (1718-1778), was a British diplomatist and politician. From 1744 to 1746 he was ambassador at Venice and from 1749 to 1751 he represented his country at The Hague. In 1751 he became Secretary of State for the Southern Department, transferring in 1754 to the Northern Department, and he remained in office until March 1761, when he was dismissed by George III in favor of the Earl of Bute, although he had largely been a cipher in that position to the stronger personalities of his colleagues, successively the Duke of Newcastle, Thomas Robinson, Henry Fox, and William Pitt. From 1771 to 1776 he acted as governor to two of the King's sons, a solemn phantom as Horace Walpole calls him. He left no sons, and all his titles became extinct except the Barony of Conyers, which had been created by writ in 1509 in favor of his ancestor Sir William Conyers (d. 1525). In that peerage he was succeeded by his daughter, Amelia.

|- style="text-align: center;" | width="30%" |Preceded by:
The Duke of Newcastle | width="40%" style="text-align: center;" |Secretary of State for the Northern Department
1754–1761 | width="30%" |Succeeded by:
The Earl of Bute

|- style="text-align: center;" | width="30%" |Preceded by:
William Pitt | width="40%" style="text-align: center;" |Secretary of State for the Southern Department
1756–1757 | width="30%" |Succeeded by:
William Pitt

|- style="text-align: center;" | width="30%" |Preceded by:
The Duke of Dorset | width="40%" style="text-align: center;" |Lord Warden of the Cinque Ports
1765–1778 | width="30%" |Succeeded by:
The Lord North