The Manhattan Rebellion or Manhattan Incident was a failed coup attempt by officers of the Royal Thai Navy against the government of Prime Minister Plaek Pibulsonggram (Phibun) on 29–30 June 1951.
At a ceremony for the official-handing over of the US dredge boat Manhattan to the Royal Thai Navy, a group of naval officers abducted Phibun and took him aboard the Navy's flagship HTMS Sri Ayudhya, where he was held hostage. Negotiations between the government and the coup organizers swiftly broke down, and violent street fighting between naval personnel and Royal Thai Army troops broke out in Bangkok. The Royal Thai Air Force bombed and sank the Sri Ayudhya despite Phibun being on board. The prime minister had to swim ashore along with the ship's crew. After losing their hostage, the sailors and marines who had participated in the coup were forced to surrender.
This event led to the Navy being stripped of most of its power and influence. It also showed that political power actually lay with commanders of the Armed Forces rather than the prime minister.