Sydney is Australia's largest city and a center of business, trade, finance, tourism and education. Sydney plays an important role in Australia's national economy, with its GDP accounting for about 30% of Australia's total. The service industry is the main body of Sydney's economy, of which the finance and insurance industry accounts for 44% of Australia's industry output value, real estate accounts for 41%, wholesale trade accounts for 38%, catering and entertainment accounts for 36%, manufacturing accounts for 35%, and the construction industry accounts for 34%. Retail trade accounts for 32%. The Reserve Bank of Australia and the Australian Securities Exchange (ASX) are both in Sydney. 40 of Australia's 53 banks are headquartered in Sydney. Three-quarters of the largest 100 companies have set up corporate headquarters or branches in Sydney. . Almost all international business people visiting Australia visit Sydney. At the same time, most of the world's leading multinational companies also have branches or offices in Sydney.

In September 2003, Sydney's unemployment rate was 5.3%. In December 2005, Sydney recorded the highest median property price among Australia's capital cities at A$485,000. Sydney is the sixth most expensive city in the world, according to the Economist Global Intelligence Living Index survey. A UBS survey ranked Sydney 26th in the world in terms of net income.

According to a report published by the Organization for Economic Co-operation and Development in November 2005, Australia has the most overvalued buildings in the Western world, with prices 52% higher than their certified rental values.

The largest industries in the Sydney economy with the largest number of employed people include property and business services, retail, manufacturing, and health and social services. Since the 1980s, jobs have migrated from manufacturing to services and information industries.

Sydney has developed into Australia's largest group and financial center. Sydney is the national headquarters of the Australian Stock Exchange, the Reserve Bank of Australia, and many of the country's banks and Australian groups. Sydney is also the regional headquarters of many multinational groups. Twentieth Century Fox has a major studio in Sydney. Sydney Futures Exchange is one of the largest financial futures and options exchanges in the Asia-Pacific region, with a total contract value of A$64.3 million in 2005. Sydney Futures Exchange is the 12th largest futures market in the world and the 19th largest futures and options market.