The Australian Opera and Ballet Orchestra existed from 1991 to 2017. Based in Sydney, New South Wales, Australia, it was is a full-time salaried orchestra managed by Opera Australia, one of three salaried orchestras in Sydney (along with the The Sydney Symphony Orchestra and the Australian Chamber Orchestra).

The orchestra was established in 1967 as The Elizabethan Sydney Orchestra, when the Australian Elizabethan Theatre Trust split its orchestra between Melbourne and Sydney (the Melbourne orchestra was The Elizabethan Trust Melbourne Orchestra).

In 2017, the orchestra was renamed as the Opera Australia Orchestra.