Sydney is the capital city of the state of New South Wales, and the most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about 70 km towards the Blue Mountains to the west, Hawkesbury to the north, the Royal National Park and Macarthur to the south and south-west. Greater Sydney consists of 658 suburbs, spread across 33 local government areas. Residents of the city are colloquially known as "Sydneysiders". The estimated population on June 2022 was 5,297,089; the city is home to approximately 66% of the state's population. Notable nicknames of the city include the "Emerald City" and the "Harbour City".

Sydney has hosted major international sporting events such as the 2000 Summer Olympics. The city is among the top fifteen most-visited cities in the world, with millions of tourists coming each year to see the city's landmarks. The city has over 1,000,000 ha of nature reserves and parks, and its notable natural features include Sydney Harbour and Royal National Park. The Sydney Harbour Bridge and the World Heritage-listed Sydney Opera House are major tourist attractions. Central Station is the hub of Sydney's rail network, and the main passenger airport serving the city is Kingsford Smith Airport, one of the world's oldest continually operating airports.

There are over 451,000 businesses based in Sydney, including 48% of the top 500 companies in Australia and two-thirds of the regional headquarters of multinational corporations. Global companies are attracted to the city in part because its time zone spans the closing of business in North America and the opening of business in Europe. Most foreign companies in Sydney maintain significant sales and service functions but comparably less production, research, and development capabilities. There are 283 multinational companies with regional offices in Sydney.