The proliferation of terrorism laws and counter-terrorism strategies reflect how important it is for all states to fight against terrorism. Terrorism is a severe criminal phenomenon that widely impacts on a state’s security and that of its citizens. It is a serious ongoing problem for Thailand, and it has become one of the biggest challenges for the Thai government today. Terrorism in Thailand is currently taking place in the southern part of the country, mainly in the three provinces of Pattani, Yala, and Narathiwat. Thus, the state’s capability to deal with terrorism becomes vital. Apart from examining how terrorism laws and counter-terrorism policies have been established, the focus shall be placed further on whether such programmes have been working effectively and legitimately. This research examines Thailand’s counter terrorism strategies in so far as they have legal impacts in criminal law, including criminal offences, criminal procedure laws, and special military laws which have been applied in the south of Thailand. Critical account will be taken, in particular, with regard to notions of ‘efficacy’ and ‘legitimacy’. These objectives will be achieved through detailed legal document analysis in Thailand and fieldwork responses by participants such as police officers, prosecutors, judges, defence lawyers and NGOs. A subsidiary aspect of the research is to draw some lessons from the England and Wales experiences of counter terrorism laws.