George Grenville was born at Wotton House on 14 October 1712. He was the second son of Richard Grenville and Hester Temple (later the 1st Countess Temple). He was one of five brothers, all of whom became MPs. His sister Hester Grenville married the leading political figure William Pitt. His elder brother was Richard Grenville, later the 2nd Earl Temple. It was intended by his parents that George Grenville should become a lawyer.