Hangzhou (Chinese: 杭州) is the capital and most populous city of Zhejiang Province in East China. It sits at the head of Hangzhou Bay, which separates Shanghai and Ningbo. Hangzhou grew to prominence as the southern terminus of the Grand Canal and has been one of the most renowned and prosperous cities in China for much of the last millennium. The city's West Lake, a UNESCO World Heritage site immediately west of the city, is among its best-known attractions.

Hangzhou is classified as a sub-provincial city and forms the core of the Hangzhou metropolitan area, the fourth-largest in China. During the 2010 Chinese census, the metropolitan area held 21.102 million people over an area of 34,585 km2 (13,353 sq mi). Hangzhou prefecture had a registered population of 9,018,000 in 2015, repeatedly rated as the best commercial city in the mainland of China. As the headquarters of Internet industry enterprises such as Alibaba, awarded the 2022 Asian Games, an emerging technology hub and home to the e-commerce giant Alibaba, also hosted the eleventh G20summit in 2016.