Thai or Foreign nationals may find themselves embroiled in the Thai criminal justice system for a variety of offenses including theft, assault, murder, business offenses such as fraud, and violations of various administrative acts and regulations. Additionally, many foreigners are also arrested for drug offenses, visa overstays and visa fraud.

The Thailand Criminal Law System has both similarities and differences with the criminal law systems of other countries. In general, the Thailand police have a certain degree of discretionary power to make arrests.  However in recent years amended constitutional provisions have provided for judicial review of detention and searches made by the Thai police.

A criminal case typically begins with an investigation by the police, investigators from an administrative section of the Thai government or private investigators. Once enough evidence is established to file a criminal case, bail may be requested.  Bail amounts and conditions may be different for foreigners than for Thais.

A judge rather than a jury will hear the case, and must decide whether the accused is guilty beyond reasonable doubt.