The Referendum Party was a Eurosceptic, single-issue political party that was active in the United Kingdom from 1994 to 1997. The party's sole objective was for a referendum to be held on the nature of the UK's membership of the European Union (EU). Specifically, it called for a referendum on whether the British electorate wanted to be part of a federal European state or to revert to being a sovereign nation that was part of a European free-trade bloc without wider political functions.

The Referendum Party was founded by the Anglo-French multi-millionaire businessman and politician James Goldsmith in November 1994. A Eurosceptic who had previously had close links to the UK's governing Conservative Party, he was also an elected Member of the European Parliament for the Movement for France party. He used his financial resources and contacts to promote the new venture, in which he was assisted by other former Conservatives. The party's structure was centralised and hierarchical, giving Goldsmith near-total control over its operations. Although not offering party membership, it claimed to have 160,000 registered "supporters", a number that was probably an exaggeration. The party gained a Member of Parliament (MP) for two weeks in 1997, when George Gardiner, the MP for Reigate, defected to it from the Conservatives shortly before that year's general election.

In the build-up to the May 1997 general election, the Referendum Party spent more on press advertising than either the incumbent Conservatives or their main rival, the Labour Party. It stood candidates in 547 of the 659 constituencies, more than any minor party had ever fielded in a UK election. Ultimately the party gained 811,827 votes, representing 2.6% of the national total; it failed to win any seats in the House of Commons. Support was strongest in southern and eastern England, and weakest in inner London, northern England, and Scotland. Following the election, psephologists argued that the impact of the Referendum Party deprived Conservative candidates of victory in somewhere between four and sixteen parliamentary seats. In the months following the election, the party renamed itself the Referendum Movement. Goldsmith died in July 1997, and the party disbanded shortly afterward. Some of its supporters reformed as a Eurosceptic pressure group called the Democracy Movement while many others joined Eurosceptic political parties like the UK Independence Party and the Democratic Party.

The United Kingdom joined the European Communities (EC) in 1973. Following the Maastricht Treaty in 1993 the EC became the European Union.The UK's ratification of the treaty in 1992, followed by its passing of the European Communities (Finance) Act in 1994–95, generated much controversy and infighting within the UK's Conservative Party, which was then in government under Prime Minister John Major. This caused considerable damage to Major's administration, which was increasingly unpopular among the British population. Various British newspapers, among them The Sun, The Daily Telegraph and The Times, had adopted a consistently Eurosceptic position. Opinion polls suggested growing opposition to aspects of the EU in the UK. More widely, the acceleration of the EU's integration process had resulted in the growth of Eurosceptic parties across many of its member states.

The Anglo-French businessman James Goldsmith announced the formation of the Referendum Party on 27 November 1994. Goldsmith had once been a strong supporter of the EC but had grown disenchanted with it during the early 1990s, becoming particularly concerned that it was forming into a superstate governed by centralised institutions in Brussels. He opposed the Maastricht Treaty, believing that it resulted in increased German dominance in Europe. As an economic protectionist, he was also critical of the EU's signing of the General Agreement on Tariffs and Trade, believing that global free trade would damage both the EU's economy and his own business interests.

Goldsmith had prior political experience, having been elected as a Member of the European Parliament (MEP) in France as part of the Eurosceptic Movement for France coalition in June 1994. Although his father had been a Member of Parliament representing Britain's Conservative Party, and he had personally had a close relationship to the party when it was led by Margaret Thatcher, Goldsmith wanted to launch his campaign independently of the Conservatives, hoping that it could draw on cross-party concerns about the direction of the EU. At the time of the party's formation, Goldsmith had an estimated personal wealth of £800 million, and promised to put £20 million into the party. He pledged to spend at least £10 million on campaigning for the next general election, to ensure that his party was funded to the same extent as the country's larger political parties. Goldsmith's intervention in British politics has been compared with that of the multi-millionaires Ross Perot in the United States and Silvio Berlusconi in Italy.

"Let me make just one promise, just one vow. We the rabble army, we in the Referendum Party, we will strive with all our strength to obtain for the people of these islands the right to decide whether or not Britain should remain a nation."

According to the political scientists Matthew Goodwin and Robert Ford, the Referendum Party was "a classic single-issue party". Similarly, the political scientists Neil Carter, Mark Evans, Keith Alderman, and Simon Gorham described it as a "single-issue movement" that had attributes of both a political party and a pressure group. While it took part in elections, it focused on a single issue and stated that if it got Members of Parliament (MP) elected their sole aim would be to secure a referendum. It also claimed that on achieving its main aim, the party would disband, unlike most political parties; as Goldsmith put in his October 1995 "Statement of Aims": "This is a single-issue biodegradable party which will be dissolved once we have achieved our aim."