English statesman, the brother-in-law of William Pitt, under whom he served as first lord of the Admiralty.

The eldest son of Richard Grenville (d. 1727) and Hester, afterward Countess Temple, he was educated at Eton and was member of Parliament from 1734 to 1752. In 1752 he inherited his mother's title together with the estates of Stowe and Wotton and took his mother's maiden name of Temple in addition to his own surname of Grenville. From the time of the marriage in 1754 of his sister Hester to William Pitt (Pitt, William, the Elder), Temple's career was linked with that of his new brother-in-law.

In November 1756 Temple became first lord of the Admiralty in the ministry of the Duke of Devonshire and Pitt. He was disliked by King George II, who dismissed both him and Pitt from office in April 1757. But when the coalition Cabinet of the Duke of Newcastle and Pitt was formed in June of the same year, Temple received the office of keeper of the privy seal. He alone in the Cabinet supported Pitt's proposal to declare war with Spain in 1761, and they resigned together in October. From this time Temple became one of the most violent and factious of politicians, and it is difficult to account for the influence that he exerted over his brother-in-law.

By 1765, however, the old friendship between the brothers-in-law was dissolving; and when at last in June 1766 Pitt consented to form a government, Temple refused to join, being bitterly offended because, although offered the head of the Treasury, he was not to be allowed an equal share with Pitt in nominating to other offices. Temple then began to inspire the most virulent libels against Pitt; and with his brother George Grenville he concentrated the whole Grenville connection against the government. After George Grenville's death in 1770 Temple retired almost completely from public life.