Fighting occurred along India's border with China: east of Bhutan about the North-East Frontier Agency of India; and, west of Nepal, about the Ladakh region of India and for control of Aksai Chin.

There had been a series of violent border skirmishes between the two countries after the 1959 Tibetan uprising, when India granted asylum to the Dalai Lama. Chinese military action grew increasingly aggressive after India rejected proposed Chinese diplomatic settlements throughout 1960-62, with China re-commencing previously banned "forward patrols" in Ladakh after 30 April 1962. Amidst the Cuban Missile Crisis, China abandoned all attempts towards a peaceful resolution on 20 October 1962, invading disputed territory along the 3,225-kilometre (2,004 mi) border in Ladakh and across the McMahon Line in the northeastern frontier. Chinese troops pushed back Indian forces in both theatres, capturing all of their claimed territory in the western theatre and the Tawang Tract in the eastern theatre. The conflict ended when China unilaterally declared a ceasefire on 20 November 1962, and simultaneously announced its withdrawal to pre-war position, also known as the "Line of Actual Control" (i.e., the effective China""India border).

Much of the fighting comprised mountain warfare, entailing large-scale combat at altitudes of over 4,000 metres (13,000 feet). Notably, the war took place entirely on land, without the use of naval or air assets by either side.

As the Sino-Soviet Split deepened, the Soviet Union made a major effort to support India, especially with the sale of advanced MiG fighter-aircraft. Simultaneously, the United States and the United Kingdom refused to sell advanced weaponry to India, further compelling it to turn to the Soviets for military aid.