While the population is aging rapidly in developed countries, significant increases in the elderly population are also observed in developing countries. The increase in the elderly population may lead to a number of macroeconomic problems for countries. The aim of this study is to investigate the impact of population ageing on external debt for emerging and developing countries. The study covers the period 1996-2019 and the system-generalised method of moments (GMM) is used. The findings show that population ageing has a positive effect on external debt. This result supports the hypothesis that the high expenditures of the elderly population such as health and pensions will deepen the budget deficit and increase external borrowing. Therefore, an increase in external debt due to population ageing can be expected in developing economies. It was also determined that economic growth decreases external borrowing. There is no statistically significant effect of trade openness on external borrowing. International reserves has a positive impact at 10% significance level. As a result, it can be said that the authorities should accelarate economic growth in order to reduce the need for external borrowing and implement policies to mitigate the effect of population ageing on government expenditures.