Current educational policy and practice are failing the 77 million out-of-school children globally, 41 million of whom live in conflict-affected fragile states (CAFS). This research seeks to identify the factors affecting access to primary education for children in CAFS and to define the mechanisms by which certain factors act as barriers. It does so through a comprehensive review of the literature and field-based case studies of access barriers in Afghanistan and Democratic Republic of Congo (DRC). Most of the literature describes approaches to increasing access that address supply- and demand-side solutions separately. This study suggests the need to integrate supply- and demand-side thinking on both access barriers and the interventions designed to overcome them. The paper will recommend existing and promising practices that, within a framework of intersecting barriers, could become viable solutions to expanding primary school access in CAFS.