This chapter explores Thai business groups throughout the transition from a lower to an upper-middle-income status. Import substitution industrialization was a feature of the 1960s and 1970s, whereas export-oriented industrialization and the Asian financial crisis occurred during the 1980s and 1990s. The chapter also examines the rise of money and capital markets and formation of Thai business group senior executives.In addition, this chapter covers the economic performance of Thailand, including GDP growth rate and export value over the past two decades. During this interval, GDP growth rate further declined. The structure of Thai high-tech export products has relied primarily on multinational corporations (MNCs). By contrast, Thai companies concentrate on agricultural and labour-intensive sectors. Thailand is a newly agro-industrialized country (NAIC) focused on agriculture rather than a newly industrialized country (NIC) focused on manufacturing. Since the 2010s, export markets have shifted from the Pacific trade triangle to Asianization. Changes in indicators such as wage levels, labour productivity, and research and development (R&D) activities in Thailand and East Asian countries are also investigated.