The Pearl River Delta Metropolitan Region is the low-lying area surrounding the Pearl River estuary, where the Pearl River flows into the South China Sea. Referred to as the Guangdong–Hong Kong–Macao Greater Bay Area in official documents, the region is one of the most densely populated and urbanized regions in the world, and is considered a megacity by numerous scholars. It is currently the wealthiest region in Southern China and one of the wealthiest regions in China along with the Yangtze River Delta in Eastern China and Jingjinji in Northern China. Most of the region is part of the Pearl River Delta Economic Zone, which is a special economic zone of China.

The Pearl River is an extensive river system in southern China. "Pearl River" is often also used as a catch-all for the watersheds of the Pearl tributaries within Guangdong, specifically the Xi ('west'), Bei ('north'), and Dong ('east'). These rivers all ultimately flow into the South China Sea through the Pearl River Delta. Measured from the farthest reaches of the Xi River, the 2,400-kilometer-long (1,500 mi) Pearl River system constitutes China's third-longest, after the Yangtze River and the Yellow River, and its second largest by volume, after the Yangtze. The 453,700 km2 (175,200 sq mi) Pearl River Basin drains the majority of Guangdong and Guangxi provinces, as well as parts of Yunnan, Guizhou, Hunan and Jiangxi; it also drains the northernmost parts of Vietnam's Northeast Cao Bằng and Lạng Sơn provinces. The Pearl River is famed as the river that flows through Guangzhou.