This paper argues that demobilization, disarmament and reintegration (DDR) trajectories of non-state armed groups are shaped by a group’s internal organization. Extensive research by political scientists has demonstrated a correlation between internal features of armed groups and their behaviour (e.g. extent of violence used against local communities). I extend this analysis to DDR outcomes by illustrating how two features of an armed group’s internal organization – command profile and financing architecture – influence post-conflict DDR trajectories. To substantiate the theory, four case studies from Colombia, Nepal and Libya are reviewed. The article concludes with the limitations and opportunities of this approach, including the potential of predicting DDR challenges.