The Siamese revolution of 1932 or Siamese coup d'état of 1932 (Thai: การปฏิวัติสยาม พ.ศ. 2475 or การเปลี่ยนแปลงการปกครองสยาม พ.ศ. 2475) was a coup d'état by the Khana Ratsadon (People's Party), included Pridi Banomyong and Plaek Phibunsongkhram, that ended the absolute monarchy of the Rattanakosin Kingdom under the Kings of Siam, occurred in Thailand (Siam) on 24 June 1932. It resulted in a bloodless transition of Siam into a constitutional monarchy, the introduction of democracy and the first constitution, and the creation of the National Assembly of Thailand. The causes were a discontent from economic crisis, lack of competent absolute monarchy government and the rise of western-educated commoners.

King Prajadhipok was still on the throne and compromised with the Khana Ratsadon. Two coups occurred a year after, in April and June amid infighting within the government over Pridi Banomyong's socialist economic plan and a fight back of the royalists.