In international standardisation, ICP-ANACOM directly accompanied the standardisation activities of the European Telecommunications Standardisation Institute (ETSI) and the International Telecommunications Union (ITU), in the context of its Telecommunications Standardisation Sector (ITU-T) and particularly in the Telecommunications Standardisation Advisory Group (TSAG). To that end it promoted a workshop on Divulgation of ITU-T International Standardisation, held in Portugal in June 2002.

By means of the co-operation protocol with the national standardisation body, the Portuguese Quality Institute (IPQ), ICP-ANACOM is the body with sectorial standardisation functions (known as ONS/ANACOM) for the areas of communications (telecommunications and postal service) and electromagnetic compatibility. ONS/ANACOM co-ordinated and supported national participation in the relevant standardisation activities of European and global standardisation bodies, and prepared ONS/ANACOM replies to IPQ consultations on opinions, public surveys and national votes on the standardisation documents of those bodies.