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.
Today, the Athenaeum Theatre is used for a range of theatre, comedy and music performances, including as a principal venue for the Melbourne International Comedy Festival and Melbourne Opera. The Wheeler Centre for Books, Writing and Ideas presents discussions and talks at the theatre. The Hillsong Church also uses the theatre for its Sunday services.
The subscription library has a 30,000-strong collection and hosts regular events, talks, book clubs and a screen club.
Melbourne Athenaeum is not related to the nearby Athenaeum Club.