Anglo-Thai Peace Treaty

The Anglo-Thai Peace Treaty signed in Singapore on 1 January 1946 ended the state of war that had existed between Thailand and the United Kingdom since the former's declaration of war of 25 January 1942 during World War II. Although the Thais had also declared war on the United States on the same day, the latter refused to recognise the legality of the declaration in light of the Japanese invasion of Thailand on 8 December 1941.

The main effect of the peace treaty was to undo the Thai annexation of the Shan States and four of the Unfederated Malay States. The British achieved less than they had hoped, largely because the United States opposed any punitive action against Thailand. They were unable, for instance, to reduce the size of Thai armed forces. The treaty did require the free delivery of up to 1.5 million tons rice, which was in surplus in Thailand, to British Malaya, where there was a shortage. It also forbade the Thais from building a canal across the Kra peninsula, which clause undercut the authority of Pridi Banomyong's government.

After its enactment, the United States and Britain restored diplomatic relations with Thailand on 5 January. The next day a general election was held. After the treaty, the United States lent $10,000,000 to Thailand for the reconstruction of her transportation network, heavily damaged by American bombing. Thailand joined the United Nations on 16 December 1946.

A separate Australian–Thai Peace Treaty, required by the Australian declaration of war of 2 March 1942 and the adoption of the Statute of Westminster, was signed on 3 April 1946.