This paper examines the possible impact of a longer school day on student learning. We specifically analyze the Jornada Escolar Extendida program (JEE), which significantly increased the school-day length of public schools in the Dominican Republic from 4 to 8 hours, and exploit its gradual implementation over time and by geographical area. For this purpose, we apply an event study approach using national tests scores data for secondary students during the 2010-2019 period, which is matched with the administrative data of the JEE implementation at the school level. Although we find a relatively low and not so stable pattern of the JEE impact on secondary students tests scores, the evidence suggests that the program generated relevant changes on learning gender gaps. In particular and consistent with the previous literature, the program seems to have favored girls learning in the low-stakes evaluation and improved boys relative scores in the high-stakes exams. However, we do not find such a clear heterogeneity impact between subjects where girls or boys have a typical relative learning advantage.
