OECD countries list 2026: all 38 member states
As of 2026 the OECD counts 38 member states, spanning from the 20 founding countries that signed on in 1961 to Costa Rica, the most recent entrant in 2021, with the organisation headquartered in Paris.
The context
What the OECD is and who belongs
The Organisation for Economic Co-operation and Development was founded in 1961, when its convention, signed in Paris the previous December, entered into force. It is the direct successor to the Organisation for European Economic Co-operation (OEEC), the body that had coordinated Marshall Plan reconstruction aid among Western European states since 1948. Widening that mandate to include North America and, later, countries well beyond Europe, is what turned the OEEC into the OECD.
The organisation is headquartered at the Château de la Muette in Paris, and its core mission is to help governments design better policy using shared data and peer comparison rather than binding treaties. Member countries submit economic, social, tax and education statistics that feed OECD reports, country reviews and recommendations covering everything from pension design to AI governance.
Membership overlaps with several other international groupings but is not identical to any of them. Most G7 and G20 economies are OECD members (see our G7 and G20 guide), and most EU countries belong to the OECD too, though the two lists diverge (compare with our EU countries list). The OECD’s membership stretches beyond Europe to include the Americas, Asia-Pacific and Israel.
| Country | Joined |
|---|---|
| Australia | 1971 |
| Austria | 1961 |
| Belgium | 1961 |
| Canada | 1961 |
| Chile | 2010 |
| Colombia | 2020 |
| Costa Rica | 2021 |
| Czechia | 1995 |
| Denmark | 1961 |
| Estonia | 2010 |
| Finland | 1969 |
| France | 1961 |
| Germany | 1961 |
| Greece | 1961 |
| Hungary | 1996 |
| Iceland | 1961 |
| Ireland | 1961 |
| Israel | 2010 |
| Italy | 1961 |
| Japan | 1964 |
| Latvia | 2016 |
| Lithuania | 2018 |
| Luxembourg | 1961 |
| Mexico | 1994 |
| Netherlands | 1961 |
| New Zealand | 1973 |
| Norway | 1961 |
| Poland | 1996 |
| Portugal | 1961 |
| Slovakia | 2000 |
| Slovenia | 2010 |
| South Korea | 1996 |
| Spain | 1961 |
| Sweden | 1961 |
| Switzerland | 1961 |
| Türkiye | 1961 |
| United Kingdom | 1961 |
| United States | 1961 |
Six countries are currently in accession talks the OECD opened in 2022: Argentina, Brazil, Bulgaria, Croatia, Peru and Romania. None of them had completed the process as of this writing, and accession can take years, since it requires each candidate to align its laws and regulatory practices with dozens of OECD legal instruments before existing members sign off.
That slow, consensus-based path is one of the clearest contrasts with rival blocs. Where the European Union binds members through common law and institutions, and BRICS has expanded quickly around a handful of large emerging economies, OECD membership stays a narrower club built around shared statistical standards and policy review rather than trade preferences or political alignment.