Tehri dam is the main dam of the Tehri Hydel Project, a major power project located near Tehri in the state of Uttaranchal in India. Towering 855 feet, the main dam at Tehri is 5th tallest dam in the world. The dam's projected capabilities include an power generation capacity of 2400 MW, stabilise irrigation to an area of 6,000 km² and add another area of 2,700 km², and a supply of 270 million gallons of drinking water to industrialized cities in Delhi, Uttar Pradesh and Uttaranchal.

The dam project was approved in 1972 and construction was started in 1978. The Tehri Hydel Development Corporation (THDC) was constituted in 1989 to supervise the construction of the dam. The main dam of the project is built near the old Tehri town that lies at the confluence of the rivers Bhagirathi, (one of the major tributary of the river Ganga) and Bhilangana.

This dam has been the object of intense protests from environmental groups and the people of this region. The issue of relocation of more than 1 lakh people of the area has resulted in protracted legal battles and has delayed the project. Besides this, environmental concerns regarding the location of large dams in the fragile ecosystem of the Himalayan foothills, there are also concerns regarding the dam's safety.