The military history of India dates back several millennia. The first reference to armies is found in theVedasand the epicsRamayanaandMahabaratha. There were many powerful dynasties in India such as theSikh Empire,Maha Janapadas, Shishunaga Empire,Gangaridai Empire, Nanda Empire, Maurya Empire,Sunga Empire, Kharavela Empire, Kuninda Kingdom,Chola Empire, Chera Empire, Pandyan Empire,Satavahana Empire, Western Satrap Empire, Kushan Empire,Vakataka Empire, Kalabhras Kingdom, Gupta Empire, Pallava Empire, Kadamba Empire, Western Ganga Kingdom, Vishnukundina Empire, Chalukya Empire, Harsha Empire, Shahi Kingdom, Eastern Chalukya Kingdom, Pratihara Empire, Pala Empire,Rashtrakuta Empire, Paramara Kingdom, Yadava Empire, Solanki Kingdom,Western Chalukya Empire,Hoysala Empire, Sena Empire, Eastern Ganga Empire,Kakatiya Kingdom, Kalachuri Empire, Delhi Sultanate,Deccan Sultanates,Ahom Kingdom, Vijayanagar Empire, Mysore Kingdom, Mughal Empire, Maratha Empire, etc.

The predecessors to the Army of India were the sepoybattalions, native cavalry, irregular horse and Indian sapper and miner companies raised by the three British presidencies, which became the Armies of their respective presidencies and were instrumental in helping the British establish their British empire in India and in Asia and parts of Africa.

The Army of India was raised under the British Raj in the 19th century by taking the erstwhile presidency armies, merging them and bringing them under the Crown. The British Indian Army fought in both the World Wars. During World War II, the Army of India played a crucial role in checking the advance of Imperial Japan and also fought several battles against Axis forces in northernAfrica and Italy.

Indian troops made up a substantial part of the British forces fighting the Japanese in Asia during World War II. Many of the troops that surrendered at Singapore to Japanese General Tomoyuki Yamashita, known as the "Tiger of the Orient" on February 15, 1942, were Indians. Some of these, approached as prisoners, chose to take up arms against the British with Subhash Chandra Bose, the leader of the Indian National Army fighting for Indian independence. Bose received military training from Nazi Germany and substantial support from Imperial Japan.

Indian troops fighting for the British Army made a significant impact in the CBI (China, Burma, India) theater. They were among the troops pushed out of Burma in 1942 and made up a large portion of the troops who fought their way back into Burma (1943–45).

In 1944, the Imperial Japanese Army launched an invasion from Burma into India. On the one hand, the Japanese goal was to establish a presence in India with thoughts that the populace would rise up and help kick the British out. The other thought, based on Allied attacks from India into Burma, was to deny the British a base from which to launch further attacks. The Japanese invasion was stopped in bloody fighting and, some might say, the IJA used up much of its energy in the effort leading to its increased inability to stop the next Allied push into Burma.

The armed forces succeeded the Military of British India following India's independence in 1947. After the second world war, many of the wartime troops were discharged and units disbanded. The reduced armed forces were partitioned between India and Pakistan. The Indian armed forces fought in all three wars against Pakistan and a war with the People's Republic of China. India also fought in the Kargil War with Pakistan in 1999, the highest altitude mountain warfare in history. The Indian Armed Forces have participated in several United Nations peacekeeping operations and are presently the second largest contributor of troops to the peacekeeping force.