The Geneva Amateur Operatic Society (GAOS, Geneva Musical Theatre)[1] is an English-speaking musical theatre and light opera group.

Based in Geneva, GAOS was founded in 1971 by a small group of theatre enthusiasts.

They produce three productions per season, including their traditional English pantomime in the winter.

GAOS is a nonprofit organization, its members receive no payment and the society makes a point of giving a substantial donations to various charities around Geneva.