The Netherlands is a founding member of the UN, having joined on 10 December 1945. It participates in ECE, ECLAC, ESCAP, and all the nonregional specialized agencies, and is a signatory to the Law of the Sea treaty and a member of the WTO. In addition, the Netherlands is a member of the Asian Development Bank, Council of Europe, EU, NATO, and OECD, and is a permanent observer at OAS.
On 1 January 1948, Belgium, the Netherlands, and Luxembourg established a joint customs union, Benelux; since that time, the three countries have freed nearly all of their mutual imports from quantitative restrictions. On 3 February 1958, the Benelux Economic Union was established to make it possible for each participating country to apply itself more intensively to the production for which it is best suited as well as to extend the total market for the member countries.