This paper will address the political economy of competition law in Thailand. Section II will provide a historical perspective of Thai Competition Law. Section III will show what went wrong with the law’s implementation since its promulgation in 1999. Section IV will assess the implications of the lack of competition law enforcement on business conduct and the establishment of a competition regime in Thailand. Section V will summarize major lessons learned in the Thai case that may be relevant to other developing countries considering adopting such a law or facing difficulties in its implementation. Finally, Section VI will draw conclusions on how a country can ensure successful enforcement of a competition law in the absence of a political will.