Young children first develop the social-behavioral skills needed to succeed in school from parents. However, most school-based interventions designed to bolster children's social-behavioral skills have focused on strengthening teachers' skills. This study examined the extent to which a 12-session group-based program for strengthening parenting skills, the Chicago Parent Program (CPP), could be implemented with fidelity in 12 urban schools serving a large population of young children (>95% African American or Latino) living in poverty. Parents of 380 prekindergarten students enrolled in the CPP. Data were collected on child behavior problems; parent satisfaction, attendance, and weekly practice completion; and implementation adherence and competence. Results indicated that CPP group leaders were highly adherent and competent; parents rated groups highly and attended an average of 8 sessions indicating CPP was implemented with high fidelity. Barriers and supports to implementation are reviewed, and implications for long-term sustainability of school-based interventions like CPP are discussed.