The Sydney Opera House is a multi-venue performing arts centre at Sydney Harbour in Sydney, New South Wales, Australia. It is one of the 20th century's most famous and distinctive buildings. Sydney Opera House is the largest and most famous opera house in Australia with an extensive repertoire.

Designed by Danish architect Jørn Utzon, the building was formally opened on 20 October 1973 after a gestation beginning with Utzon's 1957 selection as winner of an international design competition. The Government of New South Wales, led by the premier, Joseph Cahill, authorised work to begin in 1958 with Utzon directing construction. The government's decision to build Utzon's design is often overshadowed by circumstances that followed, including cost and scheduling overruns as well as the architect's ultimate resignation.

The building and its surrounds occupy the whole of Bennelong Point on Sydney Harbour, between Sydney Cove and Farm Cove, adjacent to the Sydney central business district and the Royal Botanic Gardens, and close by the Sydney Harbour Bridge.

Though its name suggests a single venue, the building comprises multiple performance venues which together host well over 1,500 performances annually, attended by more than 1.2 million people. Performances are presented by numerous performing artists, including three resident companies: Opera Australia, the Sydney Theatre Company and the Sydney Symphony Orchestra. As one of the most popular visitor attractions in Australia, more than eight million people visit the site annually, and approximately 350,000 visitors take a guided tour of the building each year. The building is managed by the Sydney Opera House Trust, an agency of the New South Wales State Government.

On 28 June 2007, the Sydney Opera House became a UNESCO World Heritage Site, having been listed on the (now defunct) Register of the National Estate since 1980, the National Trust of Australia register since 1983, the City of Sydney Heritage Inventory since 2000, the New South Wales State Heritage Register since 2003, and the Australian National Heritage List since 2005.