Post-compulsory education constitutes a stage of heightened vulnerability for certain young people who face conditions of inequality. Young people with disabilities or from socio-economically disadvantaged backgrounds, immigrants, Romani, and women are the primary vulnerable groups in Spain. In addition, other circumstances may present a challenge to gaining admission to, persisting in and successfully graduating from post-compulsory education. Although belonging to one of these groups does not present an obstacle for certain young people in the continuation of their studies, for others, being a member of a vulnerable group poses a challenge on a daily basis. This article seeks to identify the factors that render it difficult for young people belonging to vulnerable groups to continue their post-compulsory studies in Spain. This study has identified familial, personal, institutional, and systemic factors that may explain why certain young people do not have access to post-compulsory schooling or drop out before completing their studies.