Michael Mackintosh Foot (23 July 1913 – 3 March 2010) was a British politician who was Leader of the Labour Party and Leader of the Opposition from 1980 to 1983. Foot began his career as a journalist on Tribune and the Evening Standard. He co-wrote the 1940 polemic against appeasement of Adolf Hitler, Guilty Men, under a pseudonym.

Foot was a Member of Parliament (MP) from 1945 to 1955 and 1960 to 1992. A passionate orator, and associated with the left wing of the Labour Party for most of his career, Foot was an ardent supporter of the Campaign for Nuclear Disarmament (CND) and of British withdrawal from the European Economic Community (EEC). He was appointed to Harold Wilson's Cabinet as Employment Secretary in 1974, and he later was Leader of the House of Commons from 1976 to 1979 under James Callaghan. He was also Deputy Leader of the Labour Party under Callaghan from 1976 to 1980.

Elected as a compromise candidate, Foot served as Labour leader and Leader of the Opposition from 1980 to 1983. Not particularly telegenic, he was nicknamed "Worzel Gummidge" for his rumpled appearance. A faction of the party broke away in 1981 to form the Social Democratic Party (SDP). Foot led Labour into the 1983 general election, when the party obtained its lowest share of the vote in 65 years and the fewest parliamentary seats since 1935, which remained the case until Labour's defeat at the 2019 general election. He resigned the party leadership following the election, and was succeeded as leader by Neil Kinnock.

Foot was born in Lipson Terrace, Plymouth, Devon, the fourth son and fifth of seven children of Isaac Foot (1880–1960) and of the Scotswoman Eva Mackintosh (1877–1946). Isaac Foot was a solicitor and founder of the Plymouth law firm Foot and Bowden (which amalgamated with another firm to become Foot Anstey). Isaac Foot, an active member of the Liberal Party, served as the Liberal Member of Parliament for Bodmin in Cornwall from 1922 to 1924 and again from 1929 to 1935, and as a Lord Mayor of Plymouth.

Michael Foot's siblings included: Sir Dingle Foot MP (1905–78), a Liberal and subsequently Labour MP; Hugh Foot, Baron Caradon (1907–90), Governor of Cyprus (1957–60) and representative of the United Kingdom at the United Nations from 1964 to 1970; Liberal politician John Foot, later Baron Foot (1909–99); Margaret Elizabeth Foot (1911–65); Jennifer Mackintosh Highet (1916–2002); and Christopher Isaac Foot (1917–84). Michael Foot was the uncle of campaigning journalist Paul Foot (1937–2004) and of charity worker Oliver Foot (1946–2008).

Foot was educated at Plymouth College Preparatory School, Forres School in Swanage, and Leighton Park School in Reading. When he left Forres School, the headmaster sent a letter to his father in which he said "he has been the leading boy in the school in every way". He then went on to read Philosophy, Politics and Economics at Wadham College, Oxford. Foot was a president of the Oxford Union. He also took part in the ESU USA Tour (the debating tour of the United States run by the English-Speaking Union).

Upon graduating with a second-class degree in 1934, he took a job as a shipping clerk in Birkenhead. Foot was profoundly influenced by the poverty and unemployment that he witnessed in Liverpool, which was on a different scale from anything he had seen in Plymouth. A Liberal up to this time, Foot was converted to socialism by Oxford University Labour Club president David Lewis, a Canadian Rhodes scholar, and others: "I knew him [at Oxford] when I was a Liberal [and Lewis] played a part in converting me to socialism."

Foot joined the Labour Party and first stood for parliament, aged 22, at the 1935 general election, where he contested Monmouth. During the election, Foot criticised the Prime Minister, Stanley Baldwin, for seeking rearmament. In his election address, Foot contended that "the armaments race in Europe must be stopped now". Foot also supported unilateral disarmament, after multilateral disarmament talks at Geneva had broken down in 1933.