This chapter focuses on the implications of population dynamics on global health. The chapter describes current and future population trends in terms of population size, composition and distribution. It starts by describing demographic changes and their processes as explained by the demographic transition model. Population pyramids by age, sex and education are employed to illustrate various stages of demographic transition in different world regions. The chapter also presents how accounting for education as another source of demographic heterogeneity helps explain future population trends. Finally, the chapter discusses how changing demographic structure, composition and distribution is linked with future global health.