Macau or Macao is a special administrative region of China. It consists of the Macau Peninsula, the islands of Taipa and Coloane, the Cotai reclamation zone between Taipa and Coloane, and several smaller islets. It borders Zhuhai to the north and west, and it lies west of Hong Kong, separated by the Pearl River estuary. With a population of about 720,000 people and a land area of 32.9 square kilometres (12.7 sq mi), it is the most densely populated region in the world.

Formerly a Portuguese colony, the territory of Portuguese Macau was first leased to Portugal by the Ming dynasty as a trading post in 1557. Portugal paid an annual rent and administered the territory under Chinese sovereignty until 1887, when Portugal gained perpetual colonial rights with the signing of the Sino-Portuguese Treaty of Peking. The colony remained under Portuguese rule until the 1999 handover to China. Macau is a special administrative region of China, which maintains separate governing and economic systems from those of mainland China under the principle of "one country, two systems". The unique blend of Portuguese, French, English, Italian, and Chinese architecture in the city's downtown area has resulted in its designation as a UNESCO World Heritage Site in 2005.

Macau is famous and globally recognised for its casinos, known by the gambling industry as the gambling capital of the world. It is also one of the most visited cities in the world. The gambling industry of Macau is around seven times larger than that of Las Vegas, Nevada. As a result, the city has one of the highest GDPs per capita and GDPs per capita by purchasing power parity in the world.

Macau has a very high Human Development Index of 0.934, as calculated by the Government of Macau, and has the third-highest life expectancy in the world. The territory is highly urbanised, holding the status of the most densely populated territory on Earth; two-thirds of the region's total area is built on land reclaimed from the sea.