The Athenaeum or Melbourne Athenaeum is one of the oldest public institutions in Victoria, Australia, founded in 1839. Its building in the Melbourne City Centre consists of a main theatre hosting a range of theatre, comedy and music performances, a small studio theatre, and a subscription library. The building was added to the National Trust's Register of Historic Buildings in 1981 and is listed on the Victorian Heritage Register. The theatre is part of Melbourne's East End Theatre District.