International standards, as defined in GB/T 20000.1—2014 "Standardization work guidelines - Part 1: General terms for standardization and related activities," are "standards that are adopted and publicly issued by international standardization organizations or through international standardization organizations." After their publication, international standards are applicable worldwide and serve as the fundamental principles for trade, exchange, and technical cooperation among countries.

The three major international standardization organizations in the world are:

1. International Organization for Standardization (ISO)

2. International Electrotechnical Commission (IEC)

3. International Telecommunication Union (ITU)

In addition to ISO, IEC, and ITU, there are a dozen other bodies and authorities that issue international standards within specific professional fields, such as:

Bureau International des Poids et Mesures (BIPM)

International Atomic Energy Agency (IAEA)

International Maritime Organization (IMO)

World Health Organization (WHO)