Bangkok is the capital city of and largest urban area in Thailand. It is known in Thai as Krung Thep Maha Nakhon (กรุงเทพมหานคร) or simply Krung Thep, meaning "city of angels". Bangkok is by far the most densely populated city in Thailand with about 12 million people. Bangkok was a small trading post near the mouth of the Chao Phraya River during the Ayutthaya Kingdom in the 15th century. It eventually grew in size and became the site of two capital cities: Thonburi in 1768 and Rattanakosin in 1782.

Because of its strategic location in Southeast Asia, Siam (later Thailand) acted as a buffer-zone between the French and British colonial empires. Bangkok itself has gained a reputation as an independent, dynamic and influential city. Bangkok is the political, social and economic centre of Thailand, and one of the leading cities in Southeast Asia.

Due to the 1980s and 1990s Asian investment boom, many multinational corporations make their regional headquarters in Bangkok and the city is a regional force in finance and business. Its increasing influence on global politics, culture, fashion and entertainment underlines its status as an Alpha global city. In 2009, it was the second most expensive city in South-East Asia behind Singapore. The city's many cultural landmarks and attractions in addition to its nightlife venues has made it synonymous with exoticism. Its rapid modernization, reflected in the cityscape and the urban society, has left untouched the historic Grand Palace, Wat Arun, Vimanmek Palace Complex and hundreds of Buddhist temples draw about 10 million international visitors each year, second only to London.

Bangkok has an official population of 8,249,117 residents, while the greater Bangkok area contains some 14,565,520 (Census 2010). The capital is a center of the megalopolis of 20 million people, situated in a heavily urbanized triangle of central and eastern Thailand, which stretches from Nakhon Ratchasima to the heavily Industrialized Eastern Seaboard. Bangkok borders five other provinces: Nonthaburi, Pathum Thani, Samut Prakan, Samut Sakhon and Nakhon Pathom; all five provinces are joined in the conurbation of the Bangkok Metropolitan Area. It is served by two international airports: Suvarnabhumi Airport and Don Mueang International Airport, four rapid transit lines operated by the BTS, MRT, and the SRT, with plans to add additional lines by 2020.