Parental involvement programs aim to strengthen school-home relations with the goal of improving children’s educational outcomes. We examine the effects of a parental involvement program in Mexico, which provides parent associations with grants and information. We separately estimate the effect of the grants from the effect of the information using data from two randomized controlled trials conducted by the government during the rollout of the program. Grants to parent associations did not improve educational outcomes. Information to parent associations reduced disciplinary actions in schools, mainly by increasing parental involvement in schools and changing parenting behavior at home. The divergent results from grants and information are partly explained by significant changes in perceptions of trust between parents and teachers. Our results suggest that parental involvement interventions may not achieve their intended goal if institutional rules are unclear about the expectations of parents and teachers as parents increase their involvement in schools.