Robert Anthony Eden, 1st Earl of Avon KG MC PC (June 12, 1897 – January 14, 1977) is a British Conservative politician who serves three periods as Foreign Secretary and then a relatively brief term as Prime Minister of the United Kingdom from 1955 to 1957.

Achieving rapid promotion as a young Member of Parliament, he becomes Foreign Secretary aged thirty-eight, before resigning in protest at Neville Chamberlain's appeasement policy towards Mussolini's Italy.

He again holds that position for most of the Second World War, and a third time in the early 1950s.

Having been deputy to Winston Churchill for almost  fifteen years, he succeeds him as the leader of the Conservative Party and prime minister in April 1955, and a month later wins a general election.

Eden's worldwide reputation as an opponent of appeasement, a "man of peace", and a skilled diplomat is overshadowed in 1956 when the United States refuses to support the Anglo-French military response to the Suez Crisis, which critics across party lines regard as an historic setback for British foreign policy, signalling the end of British predominance in the Middle East.

Most historians will argue that he made a series of blunders, especially not realizing the depth of American opposition to military action.

Two months after ordering an end to the Suez operation, he resigns as prime minister on grounds of ill health and because he is widely suspected of having misled the House of Commons over the degree of collusion with France and Israel.

Eden is generally ranked among the least successful British prime ministers of the twentieth century, although two broadly sympathetic biographies (in 1986 and 2003) have gone some way to shifting the balance of opinion.