The Battle of Plassey (23 June 1757), is a decisive British East India Company victory over the Nawab of Bengal and his French allies, establishing Company rule in South Asia which expands over much of the Indies for the next hundred years.

The battle takes place at Palashi, Bengal (Plassey is the anglicised version of Palashi), on the river banks of the Bhagirathi River, about 150 km north of Calcutta, near Murshidabad, then capital of undivided Bengal.

The belligerents are Siraj-ud-daulah, the last independent Nawab of Bengal, and the British East India Company.The battle is preceded by the attack on British-controlled Calcutta by Siraj-ud-daulah and the Black Hole incident.

The British send reinforcements under Colonel Robert Clive and Admiral Charles Watson from Madras to Bengal and recaptured Calcutta.

Clive then seizes the initiative to capture the French fort of Chandernagar.

Tensions and suspicions between Siraj-ud-daulah and the British culminate in the Battle of Plassey.

The battle is waged during the Seven Years' War (1756–63), and, in a mirror of their European rivalry, the French East India Company sends a small contingent to fight against the British.

Siraj-ud-Daulah has a numerically superior force and makes his stand at Plassey.

The British, worried about being outnumbered, form a conspiracy with Siraj-ud-Daulah's demoted army chief Mir Jafar, along with others such as Yar Lutuf Khan, Jagat Seths (Mahtab Chand and Swarup Chand), Omichund and Rai Durlabh.

Mir Jafar, Rai Durlabh and Yar Lutuf Khan thus assemble their troops near the battlefield but make no move to actually join the battle.

Siraj-ud-Daulah's army is defeated by roughly 3,000 soldiers of Col. Robert Clive, owing to the flight of Siraj-ud-daulah from the battlefield and the inactivity of the conspirators.This is judged to be one of the pivotal battles in the control of South Asia by the colonial powers.

The British now wield enormous influence over the Nawab and consequently acquire large amounts of concession for previous losses and revenue from trade.

The British further use this revenue to increase their military might and push the other European colonial powers such as the Dutch and the French out of South Asia, thus expanding the British Empire in Asia.