The multilateral trading system came into being on 1 January 1948 when the General Agreement on Tariffs and Trade (GATT 1947) was signed by its 23 founding members. The GATT's membership expanded considerably in the following decades as many countries gained their independence and took over the rights and obligations of membership that metropolitan powers had accepted on their behalf, and others negotiated their accession to the treaty. All the Members of GATT 1947 decided by the end of the Uruguay Round of trade negotiations (1986–1994) to take on the greatly enlarged rights and obligations of the new organization they had negotiated – the World Trade Organization (WTO), which came into force on 1 January 1995 with 128 original Members. While these accounted for an extremely large percentage of world trade, many economies remained outside the multilateral system. Since its inception, WTO Members have repeatedly stressed their commitment to making the WTO universal in scope and coverage – an ambition shared by a large number of governments outside the system.

Since 1995 another 23 governments have negotiated their accession to the WTO, which now has 151 Members. This is an endorsement of the principles on which the Organization is based and the validity of its disciplines.