Over the last two decades, accompanying the rapid development of transnational corporations (TNCs), globalization of economic activities has made a strong impact on cities not only in developed countries, but also in developing ones. The World/Global City studies have devoted themselves to evolving a comprehensive understanding of cities under globalization, mainly in developed countries, since the 1980s. This paper outlines some perspectives on cities in developed countries within the framework of World/Global City studies, and discusses the issues and significance of applying that framework to ""mega-cities"" in Southeast Asia. The studies are divided two domains according to their perspectives on relations between cities and TNCs, who are some of the main actors in globalization. On the one hand, the World City study primarily focuses on rating cities as world cities by the number of established headquarters and regional headquarters. This implies that a world city is a base point for controlling and coordinating the New International Division of Labor (NIDL), which was initially mapped by Hymer. On the other hand, the Global City study, which is represented by Sassen, considers the ""production"" process of specialized services consequent upon interactions between firms and the agglomeration of producers in the service industry. It means that a global city is not a base point but a geographical place, such as an industrial district. Perspectives of the global city are conscious of linkages among firms within a city and the dynamics that affect the position of networks of industrial districts and hierarchy of urban systems. In Southeast Asia, we have witnessed emerging cities where major TNCs have been concentrating since the latter half of 1980s. TNC-owned manufacturing plants have been appearing in industrial parks on the outskirts of cities, whereas their commercial arms have agglomerated at city centers where office towers are being, or have been, built. These TNC locations reflect on urban structures and