Here, in no particular order, are links to the websites of some improv theatre groups and organizations in the Netherlands and elsewhere. There is a slant here towards theatre groups interested in, experimenting with, using and developing long form and experimental improv.
If your group should have a link on this page, let me know!

the Netherlands
  • AllImprov, an umbrella organisation promoting improv theatre activities in the Netherlands (in Dutch)
  • ImproCentrum, promoting top quality Dutch improv theatre activities (in Dutch)
  • TVA, the Theatresport Vereniging Amsterdam (in Dutch - with an excellent links page)
  • Boom Chicago, US-style showtime comedy improv entertainment in Amsterdam
  • DIT - Dit Is Theater, a large Dutch improv theatre and cabaret group (in Dutch)
  • CatchImpro, the latest thing in theatresports-based competitive improv
  • easylaughs, weekly international comedy improv shows in Amsterdam, plus courses and walk-in workshops

Europe

the Americas and Canada

the entire planet
  • this is the ultimate list of improv theatre groups worldwide (whether or not they are interested in long form, abstract work, etc).

the virtual world