Tengchong (Chinese: 騰衝; pinyin: Téngchōng) is a county-level city of Baoshan City, western Yunnan province, People's Republic of China. It is well known for its volcanic activity. The city is named after the town of Tengchong which serves as its political center, previously known as Tengyue (Chinese: 騰越; pinyin: Téngyuè) in Chinese. English language sources of the late nineteenth and early twentieth centuries use names such as Teng-Chung, Tingyueh, Teng Yueh, Momein and Momien.

It borders with Myanmar in the northwest for 151 km (94 mi). By road, it is 650 km (400 mi) west of the provincial capital, Kunming, and 170 km (110 mi) westward from Baoshan's urban area.

Tengchong marks the southwestern terminus of the Heihe–Tengchong Line, an imaginary line significant in geography that divides the area of China into two parts with contrasting population densities.

Tengchong is one of the earliest developed regions in Southwest China. During the Western Han dynasty (206 BC – AD 24), it belonged to Yizhou Commandery. In the Sui (581–618) and Tang (618–907) dynasties, a contemporary prefecture governed by a local chieftain was set up. In the Yuan dynasty (1271–1368), Tengyue Prefecture was instituted. In the following dynasties, different administrative offices were set up. In 1913, Tengchong was made a county. Historically, it occupied an important position on the Southwestern Silk Route. The Sichuan cloth and bamboo sticks available at the markets in Bactria (including Afghanistan and parts of India) were brought there from the ancient Bonan Route through Tengchong. From the Ming dynasty onwards, large numbers of Tengchong people went abroad to trade and seek a livelihood. The city grew wealthy from trade with Myanmar and South East Asia due to its proximity to Mandalay across the Burmese border.

In 1868, during a visit to Tengchong, British Army Major Sladen procured a woodblock printed edition of the Chinese history of the town, which was to be brought back to England and deposited at the British Museum. In the West the town is best known as the site of the murder of British diplomat Augustus Margary on February 21, 1875, an event which led to the Chefoo Convention. It was also the base of the China Inland Mission missionary James Fraser during the majority of his time working with the Lisu people. At one point British forces in British-occupied Burma established a trading post in the town with hopes of generating wealth through trade with China. In the early 20th century, a thriving cross-border trade between British-controlled Burma and China was centered around Tengchong. In 1921, construction work began on the British consulate in Tengchong, with completion 10 years later.

During World War II, the area around Tengchong was the scene of fierce battles between the Japanese who invaded from occupied Burma and combined Chinese forces of the Nationalists and communists, aided by American fighter squadrons. After the Chinese government relocated to Sichuan after the fall of Nanjing, there were grave concerns that if Yunnan fell, Japanese access to Sichuan would become relatively easy, forcing a new and cumbersome relocation, so large forces were deployed to stop the Japanese army.

The area of Tengchong is 5,693 square kilometres (2,198 sq mi).

Situated at the southwestern end of the (transversely faulted) Hengduan Mountains, Tengchong topographically assumes the form of a horseshoe with the opening facing the south. The easternmost sources of the Irrawaddy River issue from the high mountains at the summit of Mount Danaozi of Gaoligong Mountain, 3,780.2 m (12,402 ft) above sea level and the lowest point, 930 m (3,050 ft) above sea level, is in the Suqingjiang valley. The elevation of the city seat is 1,640 m (5,380 ft).