ISO is made up of its members which are divided into three categories:

• Member bodies

  A member body of ISO is the national body "most representative of standardization in its country". Only one such body for each country is accepted for membership of ISO. Member bodies are entitled to participate and exercise full voting rights on any technical committee and policy committee of ISO.

• Correspondent members

  A correspondent member is usually an organization in a country which does not yet have a fully-developed national standards activity. Correspondent members do not take an active part in the technical and policy development work, but are entitled to be kept fully informed about the work of interest to them.

• Subscriber members

  Subscriber membership has been established for countries with very small economies. Subscriber members pay reduced membership fees that nevertheless allow them to maintain contact with international standardization.

• List by country

• List by acronym