U.S. Operetta Companies:
Atlanta Lyric Theatre, Georgia: http://www.atlantalyrictheatre.com/
Chicago Folks Operetta, Oak Park: http://chicagofolksoperetta.org/
Comic Opera Guild, Ann Arbor: http://www.comicoperaguild.org/
Concert Operetta Theatre, Philadelphia: http://www.concertoperetta.com/index1.shtml
42nd Street Moon, San Francisco: http://42ndstmoon.org/
Jarvis Conservatory, Napa: http://www.jarvisconservatory.com/
Lamplighters, San Francisco: http://www.lamplighters.org/
Light Opera Works, Evanston: http://www.light-opera-works.org/
Light Opera Works History 1980-1999: http://www.lightoperaworks.info/
Lyric Theatre of San Jose: http://www.lyrictheatre.org/
Ohio Light Opera Company, Wooster: http://www.ohiolightopera.org/
Skylark Opera, Saint Paul, MN: http://www.skylarkopera.org/

Foreign Operetta Companies:
Applause! Musical Society (Vancouver, BC): http://www.applausemusicals.com/
Budapest Operetta Theatre: http://www.operettszinhaz.hu/index.php?o=0&k1=59&nyelvid=2
Opéra Comique, Paris: http://www.opera-comique.com/
StaatsOperette Dresden  http://www.staatsoperette-dresden.de/
Théâtre Athénée, Paris: http://www.athenee-theatre.com/#
Toronto Operetta Theatre: http://www.torontooperetta.com/
Volksoper, Vienna: http://volksoper.at/

Composer Societies:
Noel Coward Society http://www.noelcoward.net/
Victor Herbert Renaissance Project: http://vherbert.com/
Walter Jurmann http://jurmann.org/
Walter Jankuhn      http://www.walter.jankuhn.2fix.de/
Emmerich Kálmán: http://www.emmerichkalman.com/
Walter, Willi, and René Kollo: http://www.kollo.com/
Erich Wolfgang Korngold (unofficial site): http://www.korngold-society.org/
Charles LeCocq – Le Testament de M. de Crac: http://www.charleslecocq.de/
Ivor Novello Society: http://www.ivornovello.com/
Jacques Offenbach Society of Great Britain: http://www.offenbachsociety.org.uk
Rodgers and Hammerstein Organization: http://rnh.com/
Johann Strauss Society of Great Britain: http://www.johann-strauss.org.uk/
Franz von Suppé (in German): http://www.f-v-su.de/
Kurt Weill Newsletter: http://www.kwf.org/publications/kurt-weill-newsletter

Gilbert and Sullivan Related:
Gilbert and Sullivan Archive: http://diamond.boisestate.edu/gas/
Gilbert and Sullivan Society, Cambridge: http://www.srcf.ucam.org/gands/
Gilbert and Sullivan Society, Evanston: http://www.savoyaires.org/index.htm
Gilbert and Sullivan Society, Houston: http://www.gilbertandsullivan.org/
Gilbert and Sullivan Players, MIT: http://web.mit.edu/gsp/www/about.html
Gilbert and Sullivan Society, Seattle: http://www.pattersong.org/
Gilbert and Sullivan Society, UK: http://www.gilbertandsullivansociety.org.uk/
Gilbert and Sullivan Society, Yale University: http://www.yale.edu/gs/index.html
Grims Dyke Hotel (Gilbert country Home): http://www.grimsdyke.com/
New York Gilbert & Sullivan Players   http://nygasp.org/
Opera a la Carte: http://www.operaalacarte.org/oalc/index2.html

Miscellaneous Sites of Interest:
Ayn Rand Music: http://dismuke.org/aynrand/
Emmerich Kálmán International Operetta-Musical Conductor Competition: http://www.kalmanconductingcomp.com/
European Foundation for Operetta: http://operettenstiftung.org/
Josef Weinberger (music publisher): http://www.josef-weinberger.com/
Kurt Gänzl (author): http://footlightnotes.tripod.com/EmilySoldene.html
Opera Lounge   http://operalounge.de/
Operabase (search shows/theaters): http://www.operabase.com/index.cgi?lang=en
Operetta Heaven Holidays, C and H Travel Ltd: http://www.operettaheaven.com/
Operetta-L: http://www.lsoft.com/SCRIPTS/WL.EXE?SL1=OPERETTA-L&H=LISTSERV.UH.EDU
Operetta Research Center Amsterdam (ORCA): http://operetta-research-center.org/
Opérette (French magazine): http://perso.wanadoo.fr/anao/
Take Two Records: http://take2records.com/
UCSB Cylinder Preservation Project: http://cylinders.library.ucsb.edu/