The Conservative Monday Club (usually known as the Monday Club) was a British political pressure group, aligned with the Conservative Party, though not endorsed by it after 2001. It also had links to the Democratic Unionist Party (DUP) and Ulster Unionist Party (UUP) in Northern Ireland.

Founded in 1961, in reaction to Prime Minister Harold Macmillan's opposition to white minority rule in Southern Rhodesia, the club became embroiled in the decolonisation and immigration debate, inevitably highlighting the controversial issue of race, which has dominated its image ever since. The club was known for its fierce opposition to non-white immigration to Britain and its support for apartheid-era South Africa and Southern Rhodesia. By 1971, the club had 35 MPs, six of them ministers, and 35 peers, with membership (including branches) totaling about 10,000.

In 1982, the constitution was re-written, with more emphasis on support for the Conservative Party, but it remained autonomous from the party. In-fighting over the club's traditional Tory agenda led to many resignations in 1991. In 2001, the Conservative Party formally severed relations with the club, which had ceased to exercise significant influence, with full membership below 600.

Following a vote of the Executive Council, the organisation was formally disbanded in July 2024.

The club was founded on 1 January 1961, by four young Conservative Party members, Paul Bristol (a 24-year-old shipbroker and the club's first chairman, who left the club in 1968), Ian Greig (Membership Secretary until 1969), Cedric Gunnery (Treasurer until 1992; died 16 Mar 2023), and Anthony Maclaren. The club was formed "to force local party associations to discuss and debate party policy". Its first general policy statement deplored the tendency of recent Conservative governments to adopt policies based upon expediency and demanded that instead Tory principles should be the guiding influence. It believed that the principles needing to be reasserted included the preservation of the constitution and existing institutions, the freedom of the individual, the private ownership of property, and the need for Britain to play a leading part in world affairs.

The club disliked what it regarded as the expediency, cynicism and materialism which motivated Harold Macmillan's government. In addition it was concerned that during this period "the left wing of the Party (had) gained a predominant influence over policy" and that as a result the Conservative Party had shifted to the left, so that "the floating voter could not detect, as he should, major differences between it and the Socialists" and, furthermore, "loyal Conservatives had become disillusioned and dispirited". The club's published aims stated that it "seeks to evolve a dynamic application of traditional Tory principles".

The group brought together supporters of Rhodesia and South Africa; the main impetus for the group's formation was the Conservatives' new decolonisation policies, in particular as a general reaction to Macmillan's 'Wind of Change' speech made in South Africa. The club stated that Macmillan had "turned the Party Left", and its first pamphlet opposed these policies as indicative of the Conservative Party's move towards liberalism. The club is notable for having promoted a policy of voluntary, or assisted, repatriation for Commonwealth immigrants, a policy subsequently adopted in the 1970 Conservative Party manifesto.

The 5th Marquess of Salisbury (1893–1972), who had resigned from Macmillan's Cabinet over the Prime Minister's liberal direction, became its first president in January 1962, when he stated "there was never a greater need for true conservatism than there is today". By the end of 1963 there were eleven Members of Parliament in the Club, which then had an overall membership of about 300. The club was courted by many Conservative politicians, including the Conservative Party leader Alec Douglas-Home who was guest-of-honour at the club's annual dinners of 1964 and 1969, and Enoch Powell, who, in a speech in 1968, said that "it was due to the Monday Club that many are brought within the Conservative Party who might otherwise be estranged from it".