The economic and social prospects are daunting for the 89 million out-of-school youth who comprise nearly half of all youth in Sub-Saharan Africa. Within the next decade, when this cohort becomes the core of the labor market, an estimated 40 million more youth will drop out, and will face an uncertain future with limited work and life skills. Furthermore, out-of-school youth often are 'policy orphans,' positioned between sectors with little data, low implementation capacity, lack of interest in long-term sustainability of programs, insufficient funds, and little coordination across the different government agencies. This report provides a diagnostic analysis of the state of out-of-school youth in Sub-Saharan Africa, focusing on the 12- to 24-year-old cohort. This report also examines the decision path youth take as they progress through the education system and the factors that explain youth's school and work choices. It finds that individual and household characteristics, social norms, and characteristics of the school system all matter in understanding why youth drop out and remain out of school. In particular, six key factors characterize out-of-school youth: (i) most out-of-school youth drop out before secondary school; (ii) early marriage for female youth and (iii) rural residence increase the likelihood of being out of school; (iv) parental education level and (v) the number of working adults are important household factors; and (vi) lack of school access and low educational quality are binding supply-side constraints. Policy discussions on out-of-school youth are framed by these six key factors along with three entry points for intervention: retention, remediation, and integration. This report also reviews policies and programs in place for out-of-school youth across the continent. Ultimately, this report aims to inform public discussion, policy formulation, and development practitioners' actions working with youth in Sub-Saharan Africa.