Costume Designers Guild
Organization founded in 1953 to "promote the research, artistry and technical expertise in the field of film and television Costume Design".
http://www.costumedesignersguild.com/

Costume Society of America
Costume and fashion history, museums, art history, lectures, conservation, and scholarships. Publishes educational journal "Dress".
http://www.costumesocietyamerica.com/

Costume Society of Great Britain
Membership information and costs, calendar of events, scholarship and grant requirements, purchasable publications, and list of associated societies with contact information. Publishes educational journal "Costume"; partial index of past issues.
http://www.costumesociety.org.uk/

Friends of the Rag Archives
Collection of wearable artists who present their art both in static shows and live performances. Photographic and video archives.
http://friendsoftherag.org/

National Costumers Association
USA-based group supporting the costuming industry. Officers and Board of Directors, mission statement, events schedule, image gallery from past competitions, scholarships, list of members, and membership form.
http://www.costumers.org

Northern Society of Costume & Textiles
Founded 1977; located in the United Kingdom. Mission statement, membership information and costs, events, historic reproduction pattern sales and ordering, associated societies, and contact information.
http://www.nsct.org.uk

The Dutch Society for Costume, Lace, Fashion and Regional Dress - NVKKMS
Organization of collectors and enthusiasts. Mission statement and history, membership information, calendar, "Bulletin" newsletter and annual educational journal "Kostuum". [Frames] [Dutch/English]
http://home.hetnet.nl/~penningmeester.nvkkms/indexeng.html