This article analyzes how extending the school day by 3.5 hours in Mexican elementary schools affected time use patterns of mothers and fathers. Using a rotating panel of households with within-individual variation in access to full-time schools (2005- 2017), we find heterogeneous effects by household composition. In households with both school-age children and younger kids, both parents reduce childcare time, but mothers’ share of care activities increases, strengthening specialization patterns. Importantly, extended school days do not change female labor outcomes in these households, highlighting the need for complementary interventions covering all dependent ages. In households with only school-age children, we find no adjustments in time allocated to care by any family member, but female labor force participation increases. We also find suggestive evidence of reduced hours worked by domestic workers, consistent with these families outsourcing care to non-family members prior to the policy.