In this chapter, the author briefly describes the historical development of Human Resource Management (HRM) in Thailand. Then, she discusses the role and importance of the Human Resource (HR) business partnership with other business functions. The author reviews some HR practices in firms and identify some key factors that determine such HRM practices. The central notion of Buddhism, the national religion, to the Thai culture, the practices of "middle path," which means no encouragement of extremism, has contributed to the unique HRM and industrial relations framework of Thailand. In short, key factors that determine HRM practices in Thailand include economic and socio-political factors, development of the IR system, ownership, management development, technological development, organizational restructuring and cultural values. In other words, the changes in HRM practices in Thailand have been more driven by external factors rather than representing pro-active development internally.