There were many causes for the Sepoy mutiny.
Political causes
The policy of annexation created panic and a feeling of insecurity among the rulers of various states. Corruption and inefficiency in the administration further created political unrest and the Indians wanted to get rid of the British.

Social causes
The continuous interference of English in the basic way of living, traditional beliefs, values and norms was seen by the Indian masses as threat to their religion.
The activities of the Christian missionaries, whose objective was to convert people to their faith, led to people’s believe that the British Government wanted to eradicate their caste and convert them to Christianity.

Economic causes
The general discontentment grew rapidly and strongly among the Indian soldiers. Most of the Indian soldiers in the East India Company’s army came from peasant families which were deeply affected by their impoverished status.

Religious causes
The Sepoys were convinced that the English were conspiring to convert them to Christianity. Superior civil and military officers abused the name of Ram and Muhammad. Idolatry was denounced. Hindu gods and goddesses were ridiculed. The Religious Disabilities Act modified Hindu customs. This act enabled a convert to Christianity, to inherit his ancestral property. All this created resentment among the people.

Military causes

The Sepoys’ emoluments were very low in comparison with those of the British soldiers and their chances of promotion negligible. The loyalty of the Sepoys was further undermined by certain military reforms which outraged their religious feelings. They had an aversion to overseas service, as travel across the seas meant loss of caste for them.

Immediate Causes

The introduction of Greased cartridges in 1856 sparked the fire. The government decided to replace the old-fashioned musket, `Brown Begs` by the `Enfield rifle’. The loading process of the Enfield rifle involved bringing the cartridge to the mouth and biting of the top paper. There was a rumour among the Sepoys in January 1857 that the greased cartridge contained the fat of cow and pig, the former sacred to Hindus and latter forbidden to Muslims. The Sepoys were now convinced that the introduction of greased cartridges was a deliberate attempt to defile Hindu and Muslim religion. This sparked off the Mutiny on 29^th March 1857.