Recent questions surrounding the repatriation, rehabilitation, and reintegration of those who traveled to join the Islamic State in Iraq and Syria (ISIS), the reintegration of violent extremists in conflict zones including Somalia, Nigeria, Libya, and Mali, and the impending release of scores of homegrown violent extremists from prisons in the United States and Europe have heightened policymaker and practitioner interest in violent extremist disengagement and reintegration (VEDR). Although a number of programs to reintegrate violent extremists have emerged both within and outside of conflict zones, significant questions remain regarding their design, implementation, and effectiveness. To advance our understanding of VEDR, this report draws insights from a review of the literature on ex-combatant disarmament, demobilization, and reintegration (DDR). The literature on DDR typically adopts a “whole of society” approach, which helps us to understand how systemic factors may influence VEDR at the individual level and outcomes at the societal level. Despite the important differences that will be reviewed, the international community’s thirty-year experience with DDR—which includes working with violent extremists—offers important insights for our understanding of VEDR.