The displacement of people within their own countries due to crises such as conflicts, disasters, and the effects of climate change is a major contemporary challenge, eliciting global concern about how to protect the displaced. The vast scale of this 'internal displacement' poses far-reaching questions for key debates around humanitarian aid, development, migration, sovereignty, rights, citizenship, identity, and social change. Yet knowledge of the issue is fragmented and highly dispersed across a range of academic and policy domains. Bringing together 45 contributions by leading researchers and practitioners, the Oxford Handbook of Internal Displacement provides an essential point of reference for advancing these debates and raising the profile of internal displacement as a vital concern for research and policy agendas. The Handbook addresses eight major areas of debate in this field of research and practice. Part I presents different conceptual understandings of internal displacement from a range of the most relevant disciplinary perspectives, including philosophy and political theory, history, law, geography, and forced migration studies. Part II of the Handbook explores the different drivers of internal displacement, embedding them in their broader social, political, and historical context. Part III addresses major internal displacement dynamics and population trends in different regions of the world. Part IV highlights the material, social and economic consequences of displacement, in terms of poverty, health, education, and housing land for the displaced. Part V addresses lived experiences of internal displacement, underscoring the agency of displaced persons in making sense of and dealing with internal displacement. Part VI of the Handbook addresses key aspects of IDP assistance and protection, including legal and policy frameworks, institutional responses, and policy and operational issues arising in this response. Part VII addresses the 'end' of internal displacement and so-called 'durable solutions' for internally displaced persons, offering compelling insights into how long-term solutions have been handled and hindered in practice. Finally, Part VIII outlines the crucial role of data in understanding and responding to internal displacement.