The Conservative Party is a centre-right political party in the United Kingdom that espouses the philosophies of conservatism and British unionism. The party's official name is the Conservative and Unionist Party, which is now used only for legal purposes, with the party using Conservatives as their everyday name. As of 2014 it is the largest single party in the House of Commons with 303 MPs, governing in coalition with the Liberal Democrats, with David Cameron, the leader of the Conservative Party, as Prime Minister. It is the largest party in local government with 8,296 councillors.

The Conservative Party was founded in 1834 from the Tory Party — giving rise to the Conservatives' colloquial name of Tories — and was one of two dominant parties in the 19th century, along with the Liberal Party. In the 1920s, the Liberal vote greatly diminished and the Labour Party became the Conservatives' main rivals. Conservative Prime Ministers led governments for 57 years of the 20th century, including Winston Churchill (1940–45, 1951–55) and Margaret Thatcher (1979–90). Thatcher's tenure led to wide-ranging economic liberalisation and saw the Conservatives become the most eurosceptic of the three major parties. The party was returned to government in coalition in 2010 under the more liberal leadership of David Cameron.

As of 2014 the Conservatives are the joint-second largest British party in the European Parliament, with 20 MEPs, who sit with the soft eurosceptic European Conservatives and Reformists (ECR) parliamentary group. The party is a member of the Alliance of European Conservatives and Reformists (AECR) Europarty and the International Democrat Union (IDU).

The party is the third-largest in the Scottish Parliament and second-largest in the Welsh Assembly. They had been formally allied to the Ulster Unionist Party (UUP) as part of the Ulster Conservatives and Unionists arrangement; this electoral pact formally ended with the Northern Ireland Party's relaunch as the NI Conservatives in June 2012, allowing for autonomy on devolved matters, similar to the Welsh Conservatives and the Scottish Conservatives.