This paper evaluates the impact of extension of the school day in the context of Brazil's "Mais Educação" Extended School Day Program. Using school level longitudinal data, we find that the program reduces the dropout rates of students in all grade levels, raises the enrollment of students in grades 6-9, but reduces the enrollment of students in grades 10-12. Moreover, the estimates indicate that the impact on grade promotion is positive for students in grades 6-9, but negative for students in lower grades. Finally, the program seems to increase repetition rates for students in all grade levels.