This Mixed Migration Centre (MMC) report takes an evidence-based approach to onward migration by investigating the dynamics of onward migration and policy responses, with a focus on the East Africa region. The paper considers how the phenomenon of onward migration has been dealt with in global migration literature, including the various ways in which onward migration has been defined. The policy landscape is then explored, focusing on the national and regional policies that directly and indirectly impact on onward migration. The paper then draws from 340 4Mi1 interviews with refugees and migrants engaged in onward migration in East Africa to explore the profiles of people engaged in onward migration, their aspirations and decision-making.