Richard Edward Geoffrey Howe, Baron Howe of Aberavon, CH, PC, QC (20 December 1926 – 9 October 2015), known from 1970 to 1992 as Sir Geoffrey Howe, was a British barrister and politician who served as Deputy Prime Minister of the United Kingdom from 1989 to 1990. A member of the Conservative Party, he was Margaret Thatcher's longest-serving Cabinet minister, successively holding the posts of chancellor of the Exchequer, foreign secretary, and finally leader of the House of Commons, deputy prime minister and Lord President of the Council. His resignation from Cabinet on 1 November 1990 is widely considered to have precipitated the leadership challenge that led to Thatcher's resignation three weeks later.

Born in Port Talbot, Wales, Howe was educated at Bridgend Preparatory School, Abberley Hall School, Winchester College, and – after serving in the army as a lieutenant – Trinity Hall, Cambridge, where he read law. He was called to the bar in 1952 and practised in Wales, after which he was elected as the Conservative member of Parliament (MP) for Bebington in 1964, but lost his seat in 1966, returning to the bar. Howe became an MP again at the 1970 general election and represented various constituencies in the House of Commons until 1992. In Edward Heath's government, he was solicitor general and a minister of state; after Labour's victory in 1974, Howe became the shadow chancellor of the Exchequer in Margaret Thatcher's shadow cabinet.

Howe became Chancellor of the Exchequer upon Thatcher's victory in the 1979 general election, with his tenure characterised by a programme of radical policies with the stated intent to restore the public finances, reduce inflation and liberalise the economy. As chancellor, Howe delivered five budgets. After the 1983 general election, Howe was appointed foreign secretary, serving six years. In 1989, Thatcher replaced Howe with John Major, giving Howe the role of deputy prime minister. He resigned from the government on 1 November 1990; in his resignation letter, he criticised Thatcher's handling of relations with the EEC and further attacked Thatcher in his resignation speech to the Commons on 13 November. The speech was widely seen as the key catalyst for the leadership challenge mounted by Michael Heseltine a few days later, which led to Thatcher's resignation and her replacement by Major.

Howe retired as an MP in 1992 and was made a life peer in June of that year. Following his retirement from the Commons, Howe took on several non-executive directorships in business and advisory posts in law and academia. He retired from the House of Lords in May 2015 and died in October of the same year, aged 88.

Howe was born in 1926 at Port Talbot, Wales, to Benjamin Edward Howe, a solicitor and coroner, and Eliza Florence (née Thomson) Howe. He was to describe himself as a quarter Scottish, a quarter Cornish and half Welsh. He had one older sister, Barbara, who died of meningitis just before he was born, and a younger brother, Colin.

He was educated at three private schools: at Bridgend Preparatory School in Bryntirion, followed by Abberley Hall School in Worcestershire and by winning an exhibition to Winchester College in Hampshire. Howe was not sporty, joining the debating society instead. It was during wartime, so he was active in the Home Guard at the school and set up a National Savings group. He was also a keen photographer and film buff. A gifted classicist, Howe was offered an exhibition to Trinity Hall, Cambridge in 1945 but first decided to join the army. He did a six-month course in maths and physics. Then he did national service as a lieutenant with the Royal Corps of Signals in East Africa, by his own account giving political lectures in Swahili about how Africans should avoid communism and remain loyal to "Bwana Kingy George"; and also climbed Mount Kilimanjaro.

Having declined an offer to remain in the army as a captain, he matriculated at Trinity Hall in 1948, where he read law and was chairman of the Cambridge University Conservative Association, and on the committee of the Cambridge Union Society. He was called to the bar by the Middle Temple in 1952 and practised in Wales. On 28 August 1953, Howe married Elspeth Shand, daughter of P. Morton Shand. They had a son and two daughters. At first, his legal practice struggled to pay, surviving thanks to a £1,200 gift from his father and a prudent marriage. He served on the Council of the Bar from 1957 to 1962 and was a council member of the pressure group JUSTICE. A high-earning barrister, he was made a QC in 1965.

Choosing a parallel career in politics, Howe stood as the Conservative Party candidate in his native Aberavon at the 1955 and 1959 general elections, losing in what was a very safe Labour Party seat. He helped to found the Bow Group, an internal Conservative think tank of "young modernisers" in the 1950s; he was one of its first chairmen in 1955–1956 and edited its magazine Crossbow from 1960 to 1962. In 1958, he co-authored the report A Giant's Strength published by the Inns of Court Conservative Association. The report argued that the unions had become too powerful and that their legal privileges should be curtailed. Iain Macleod discouraged the authors from publicising the report.