The OECD originated in 1948 as the Organisation for European Economic Co-operation (OEEC), led by Robert Marjolin of France, to help administer the Marshall Plan for the reconstruction of Europe after World War II. Later, its membership was extended to non-European states. In 1961, it was reformed into the Organisation for Economic Co-operation and Development by the Convention on the Organisation for Economic Co-operation and Development. Most OECD members are high-income economies with a high Human Development Index (HDI) and are regarded as developed countries (Chile being the only OECD member which is also a member in the organisation of developing countries, the Group of 77).
The OECD's headquarters are at the Château de la Muette in Paris, France.