Tianjin Chinese: 天津; pinyin: Tiānjīn) is a metropolis in northern China and one of the five national central cities of the People's Republic of China. It is governed as a direct-controlled municipality, one of four such designations, and is, thus, under direct administration of the central government. Tianjin borders Hebei Province and Beijing Municipality, bounded to the east by the Bohai Gulf portion of the Yellow Sea.

As a dual-core city, Tianjin is divided into the old city and the Binhai New Area. Binhai New Area is a new growth pole in China, and it maintains an annual growth rate of nearly 30% of the GDP. As of the end of 2010, 285 Fortune Global 500 companies have established branch offices in Binhai. It is a base of China's advanced industry, financial reform, and innovation.

In terms of urban population, it is the sixth-largest city of the People's Republic of China, and its urban land area (Binhai New Area is not included) ranks fifth in the nation after Beijing, Shanghai, Wuhan and Guangzhou. Tianjin's urban area is located along the Hai River, which connects to the Yellow and Yangtze Rivers via the Grand Canal in Tianjin. Tianjin was once home to foreign concessions in the late Qing Dynasty and early Kuomintang (KMT) era. The municipality incorporates the coastal region of Tanggu, home to the Binhai New Area and the Tianjin Economic-Technological Development Area (TEDA).