In this chapter I will provide an overview of the global data on child migration, and explore how and why children travel in the regions covered by the various contributors to this book. At the outset, I acknowledge that data on international migration is not particularly precise or reliable. Statistics in many regions are scarce or non-existent, so that numbers are generally based on estimates. Specific data on child migration is even more difficult to come by. According to the United Nations High Commissioner on Refugees (UNHCR) in its Global Trends Report 2015, only a few countries supply refugee data disaggregated by age. In 2015, data disaggregated by age was available for 21.2 million people only, which represented 33 per cent of the estimated global number of refugees. In this chapter I draw heavily on the ground-breaking report prepared by the United Nations Children’s Fund (UNICEF) in 2015, Uprooted: The Growing Crisis for Refugee and Migrant Children, which represents a laudatory effort to compile all of the data then available on the topic of children on the move around the world.