The European Atomic Energy Community (EAEC or Euratom) is an international organisation established by the Euratom Treaty on 25 March 1957 with the original purpose of creating a specialist market for nuclear power in Europe, by developing nuclear energy and distributing it to its member states while selling the surplus to non-member states. However, over the years its scope has been considerably increased to cover a large variety of areas associated with nuclear power and ionising radiation as diverse as safeguarding of nuclear materials, radiation protection and construction of the International Fusion Reactor ITER.

It is legally distinct from the European Union (EU) although it has the same membership, and is governed by many of the EU's institutions; but it is the only remaining community organisation that is independent of the EU and therefore outside the regulatory control of the European Parliament. Since 2014, Switzerland has also participated in Euratom programmes as an associated state.

The United Kingdom ceased to be a member of the organisation on 31 January 2020. However, under the terms of the UK–EU Trade and Cooperation Agreement, the United Kingdom participates in Euratom as an associated state following the end of the transition period on 31 December 2020.