Diego Sarmiento de Acuña, Count of Gondomar

Diego Sarmiento de Acuña, Count of Gondomar (Spanish: Don Diego Sarmiento de Acuña, conde de Gondomar; Astorga, November 1, 1567 – Casalarreina, La Rioja, October 2, 1626), was a Spanish (Galician) diplomat. He served as the Spanish ambassador to England from 1613 to 1622 and afterwards, as a kind of ambassador emeritus, Spain's leading expert on English affairs until his death.

The popular notion in England of his day painted him as the head of a Spanish faction at the English court, as privy to the inner thoughts of King James I, and as a fiendish schemer for Popery. The term "Machiavellian" was brought into common English usage in references to him.