The Royal Indian Navy mutiny or revolt, also called the 1946 Naval Uprising, was an insurrection of Indian naval ratings, soldiers, police personnel and civilians against the British government in India. From the initial flashpoint in Bombay (now Mumbai), the revolt spread and found support throughout British India, from Karachi to Calcutta (now Kolkata), and ultimately came to involve over 20,000 sailors in 78 ships and shore establishments.

The mutiny was suppressed by British troops and Royal Navy warships. The Indian National Congress and the Muslim League condemned the mutiny, realising the political and military risks of unrest of this nature on the eve of independence. The Communist Party of India was the only nation-wide political organisation that supported the rebellion.

The RIN Revolt started as a strike by ratings of the Royal Indian Navy on 18 February in protest against general conditions. The immediate issues of the revolt were living conditions and food. By dusk on 19 February, a Naval Central Strike committee was elected. The strike found some support amongst the Indian population, though not their political leadership who saw the dangers of mutiny on the eve of Independence. The actions of the mutineers were supported by demonstrations which included a one-day general strike in Bombay. The strike spread to other cities, and was joined by elements of the Royal Indian Air Force and local police forces.

Indian Naval personnel began calling themselves the "Indian National Navy" and offered left-handed salutes to British officers. At some places, NCOs in the British Indian Army ignored and defied orders from British superiors. In Madras and Poona (now Pune), the British garrisons had to face some unrest within the ranks of the Indian Army. Widespread rioting took place from Karachi to Calcutta. Notably, the revolting ships hoisted three flags tied together – those of the Congress, Muslim League, and the Red Flag of the Communist Party of India (CPI), signifying the unity and downplaying of communal issues among the mutineers.

The revolt was called off following a meeting between the President of the Naval Central Strike Committee (NCSC), M. S. Khan, and Vallab Bhai Patel of the Congress, who had been sent to Bombay to settle the crisis. Patel issued a statement calling on the strikers to end their action, which was later echoed by a statement issued in Calcutta by Muhammad Ali Jinnah on behalf of the Muslim League. Under these considerable pressures, the strikers gave way. Arrests were then made, followed by courts martial and the dismissal of 476 sailors from the Royal Indian Navy. None of those dismissed were reinstated into either the Indian or Pakistani navies after independence.