International

Canada

Multiple Births Canada (MBC)

United States of America

Multiples of America (MOA)

The Center for the Study of Multiple Birth

Centre for Loss in Multiple Births 

Australia

Australian Multiple Birth Association (AMBA)

Multinet

Japan

Japanese Association of Twin Mothers (JATM)

Japanese Multiple Birth Association (JAMBA)

New Zealand

Multiples NZ

Czech Republic

Twins and Multiple Birth Clubs

Denmark

Nordic Twinnet

Finland

Finnish Multiple Births Association (FMBA)

France

Federation Jumeaux-et-Plus

Germany

ABC Club

Netherlands

Twinspiratie

Norway

Norway Twin Parents Club

Sweden

Swedish Twin Society

United Kingdom

Multiple Births Foundation

Twins and Multiple Births Association (TAMBA)