The Democracy in Europe Movement 2025, or DiEM25, is a left-wing European political alliance. It operates as a pan-European umbrella for subsidiary parties sharing the same name and branding (e.g. MeRA25, MERA25), and runs electoral lists with other affiliated parties. Despite its organisation and sometimes being referred to as a "European party" or "transnational party", DiEM25 does not meet the requirements to register as a European political party.

DiEM25 was founded by a group of Europeans, including Yanis Varoufakis and Srećko Horvat. The movement was officially launched at ceremonial events in 2016 in the Volksbühne theatre in Berlin and on 23 March in Rome.

DiEM25's tendencies are alter-globalisation, social ecology, ecofeminism, post-growth and post-capitalism. Implementation of a universal basic income is widely defended among its members.

The acronym DiEM alludes to the Latin phrase carpe diem. To highlight the urgency of democratising Europe, the movement sets the horizon for the year 2025 to draft a democratic constitution that will replace all the European treaties that are in force today. Yet, it failed to elect representatives in the European Parliament up to the 2024 European elections.

DiEM25 argues that the people of Europe need to seize the opportunity to create political organisations at a pan-European level. Its participants consider that the model of national parties forming fragile alliances in the European Parliament is obsolete and that a pan-European movement is necessary to confront the great economic, political and social crises in Europe today. In its analysis, the movement considers that these crises threaten to disintegrate Europe, and which possess characteristics that are similar to those of the Great Depression of the 1930s.

DiEM25 seeks to create a more democratic Europe. They see the European Union becoming a technocratic superstate ruled by edict. DiEM25 aims instead to make Europe a union of people governed by democratic consent through a policy of decentralisation. DiEM25 cites eight distinct elements of European governance by compulsion, the first of which is "hit-squad inspectorates and the Troika they formed together with unelected 'technocrats' from other international and European institutions". Adding that the establishment is "contemptuous of democracy" and "all political authority [must come] from Europe’s sovereign peoples".

DiEM25 would like to act as an umbrella organization, gathering left-wing parties, grassroots protest movements and "rebel regions" to develop a common response to the five crises Europe faces today, namely debt, banking, poverty, low investment and migration. Further, DiEM25 wishes to reform EU institutions, originally designed to serve industry, so that they become fully transparent and responsive to European citizens. Ultimately, DiEM25 envisions European citizens writing a democratic constitution for the European Union.

Adopting a bottom-up approach by mobilising at a grassroots level, the movement aims to reform the European Union's existing institutions to create a "full-fledged democracy with a sovereign Parliament respecting national self-determination and sharing power with national Parliaments, regional assemblies and municipal councils" in order to replace the "Brussels bureaucracy". Among others, the movement is supported by prominent American linguist and political activist Noam Chomsky, Italian philosopher Antonio Negri, American anthropologist Charles Nuckolls, American economist James K. Galbraith and former Labour MP Stuart Holland. Diverse figures including Julian Assange, film director Ken Loach, Green Party MP Caroline Lucas, British Labour politician John McDonnell, Dutch sociologist Saskia Sassen, Franco Berardi and Slovenian philosopher Slavoj Žižek are on its Advisory Panel.