Court judgments are not consistently publicly published and are difficult to find in English. Lower and Appeal court decisions are not published. Selected decisions of the Supreme Court of Justice, Supreme Administrative Court and Constitutional Court have been translated into English and are available on the following open access databases:
Constitutional Court decisions
Supreme Court of Justice decisions
Supreme Administrative Court Decisions
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As predominantly a civil law country, Thai jurisprudence is not a primary or binding source of law. The Supreme Court of Justice is not bound to follow its own decisions, and lower courts are not bound to follow precedents set by higher courts. In practice, however, the decisions of the Supreme Court are persuasive, have some precedential value, and are often used as secondary authoritative sources of law by by the Supreme Court itself and on lower courts.
The judicial branch of government consists of four court systems established by the Constitution: the Constitutional Court (established by the 1997 Constitution), the Courts of Justice, the Administrative Courts (established by the 1997 Constitution), and the Military Courts.
The Courts of Justice hierarchy is:
In 2016, a Specialised Appeal Court was established by The Act for Establishment of the Court of Appeal for Specialized Cases B.E. 2558 (2015) and began operation. The Court's jurisdiction covers appeals from decisions of the specialised courts of first instance.
More on the Specialised Appeal Court.
More on the Court system on the Thailand Court of Justice website.
For detailed commentary on the Thai court and judicial system, see The Judicial System in Thailand: An Outlook for a New Century, from the ASEAN Law Association. Note that this undated publication was written while the 1997 Constitution was still in force - please read it with this in mind.
See also Chapter 5 - 'The Constitutional Court and Constitutional Enforcement' in the following book: