The Palace Law of Succession, Buddhist Era 2467 (1924) governs succession to the Throne of the Kingdom of Thailand, under the ruling House of Chakri. Succession matters prior to the end of absolute monarchy in 1932 could be contentious, especially during the Ayutthaya period from the 14th to 18th centuries. In 1924, King Vajiravudh attempted to clarify the succession process by laying down the Palace Law of Succession. It was promulgated and came into effect in November 1924 as, in part, an attempt to eliminate the vagueness relating to succession within the Thai monarchical regime and to systematically resolve previous controversies. In 1932, after Siam became a constitutional monarchy, various amendments relating to succession were introduced. The 1997 Constitution of Thailand relied on the law with regards to succession, but the 2006 Interim Constitution made no mention of succession, leaving it to "constitutional practice". The 2007 Constitution again relied on the Palace Law. The preamble of the 2014 interim constitution of Thailand abrogated the 2007 Constitution, with the exception of chapter 2, concerning the monarchy and the succession.

The Chakri dynasty is the current reigning dynasty of the Kingdom of Thailand. The head of the house is the king, who is head of state. The family has ruled Thailand since the founding of the Rattanakosin Era and the city of Bangkok in 1782; following the end of Taksin Thonburi's reign, when the capital of Siam shifted to Bangkok. The royal house was founded by Rama I, an Ayutthaya military leader of Sino-Mon descent.