An initiative of affiliation to ICOS was begun in April 2008. The following organisations are currently affiliated to ICOS:
- Adriatic Onomastic Research Centre, University of Zadar (Croatia)
- American Name Society (USA)
- Australian National Placenames Survey (Australia)
- Center of Onomastics,Technical University of Cluj-Napoca, North University Centre of Baia Mare (Romania)
- Commission of Slavic Onomastics (Poland)
- Department of Czech Language, Faculty of Arts, University of Ostrava (Czechia)
- Department of Onomastic, Czech Language Institute, Czech Academy of Sciences (Czechia)
- Deutsche Gesellschaft für Namenforschung (GfN) e.V. (Germany)
- English Place-Name Society (UK)
- Forschungsstelle für Namenkunde, University of Berne (Switzerland)
- Greek Onomastic Society / Association Onomastique Grecque (Greece)
- International Institute of Jewish Genealogy (Israel)
- Names Society of Southern Africa (South Africa)
- NORNA (Nordic region)
- Onomastic Board of the Croatian Academy of Arts and Sciences (Croatia)
- Onomastica e Letteratura, University of Pisa (Italy)
- Onomastika Elkartea (Sociedad Vasca de Onomástica / Société Basque d’Onomastique) (Spain)
- Polish Council of Onomastics
- Polish Onomastic Society (Polskie Towarzystwo Onomastyczne) (Poland)
- Scottish Place-Name Society (Comann Ainmean-Àite na h-Alba) (UK)
- Slovak Onomastic Commission (Slovakia)
- Société française d’onomastique (France)
If you wish your organisation to be affiliated to ICOS, and thereby to enter into an arrangement for exchanging information electronically, please contact the Secretary.