This chapter shows how inequalities in education, health, employment and earnings reinforce each other and evolve over the life course. It first discusses how unequal ageing begins in childhood because of the crucial influence of early life circumstances on health and socio-economic developments later in life. It then analyses the interactions between health, education and labour market outcomes through the different stages of working life, and builds life course trajectories highlighting differentials in lifetime earnings. The chapter then focuses on trends and social disparities in disability among the over 50s in Europe, Japan and the United States. Finally, the last section zooms in on some of the key challenges in health, education and income inequalities faced by emerging economies.