This paper illustrates a small extent of co-evolution of IPR regime and technological capability of Thai automotive firms. This study analysed the primary data on Thai IP-related law, regulation, firms’ R&D and innovation surveys, patent registration, court litigation, and conducted interviews for case studies of firms, policy makers, and university professors specialised in the automotive industry. The results show that there are some atmospheric changes in terms of increasing awareness of importance of patent after the regime became stronger. The stronger patent regime has slight impacts on the extent and nature of knowledge transfer between transnational corporations and local part suppliers. Last, the stronger patent regime has impacts on firms climbing up technological ladders from production to more sophisticated activities