Thailand adopted a full-fledged competition law in 1999, after the Thai economy faced problems with automobile manufacturers halting imports of vehicles into Thailand and it was not clear whether the earlier adopted price laws could deal with this issue. Despite the efforts of the Thai government to draft a competition law based on the competition laws of South Korea and Germany, the government was not able pass an effective law. This chapter explains that the law has triggered 93 complaints, the majority related to unfair trade practices, but none of these complaints have led to a decision that the competition law was violated. The chapter purports that the ineffectiveness was mainly caused by the conceptualization of the enforcement institutions. To curb this situation, a new competition law was adopted in 2017.