Population ageing – the shift in the distribution of a population towards older ages – is a universal phenomenon and an inevitable consequence of the demographic transition. Increases in longevity reflect huge advances in access to improved nutrition, sanitation, medicine, health care, education and economic well-being. Older persons also make significant contributions to society and a shift in the population structure towards older ages can bring opportunities. Yet at the same time, population ageing presents a number of social, economic and cultural challenges to individuals, families, societies and the global community. Moreover, not all groups are affected equally by population ageing: in particular, older women as well as persons with disabilities among others often face increased discrimination and specific vulnerabilities. Forward-looking policies and programmes that take account of current and future population dynamics including population ageing are urgently needed to achieve sustainable development as articulated in the 2030 Agenda for Sustainable Development.