While population has been aging globally, regions and countries are significantly asymmetric in the timing and speed of the demographic transitions, especially between developed and developing regions. This paper explores the impacts of asymmetric demographic change on international capital flows with two contributions. First, the paper introduces demographic structure and pension systems into a theoretical overlapping-generation model of a small open economy, and derives an analytical solution which links a large set of factors to the current account. This framework enables tractable analysis of the effects of various demographic shocks on external balances, and also of the interaction between demographic shocks and productivity growth and pension systems. Second, the paper provides a comprehensive literature review of both modeling and empirical studies. There are several qualitative implications. First, the patterns of capital flows depend on the nature of demographic shocks (permanent or transitory; fertility or mortality) and also on the stage of demographic shocks. Second, less generous pension systems tend to increase national saving and drive capital outflows. Third, financial frictions such as borrowing constraints of young people tend to increase national saving and drive capital outflows. Fourth, production and trade specialization in labor-intensive sectors tends to decrease investment and drive capital outflows in the face of fertility growth. Fifth, the magnitude of the demographic effects depends on the extent of cross-border mobility of capital, labor and goods. There are also several quantitative implications. First, demographics alone can explain a significant fraction of historical current account dynamics among advanced economies, especially lowfrequency movements. Second, institutional and financial frictions need to be incorporated to reconcile the demographic effects with historical capital flows from emerging to advanced economies. Third, production structure and trade specialization also play an important role in demographics-driven capital outflows from emerging economies. On the other hand, empirical studies strongly support that the demographic change since the second half of last century has statistically significant effects on the current account balance. The current account tends to decrease in the dependency ratio, and increase in the working-age population share. This paper also points out the potential research direction.