The Building Strong Families (BSF) evaluation assessed the impacts of eight programs offering a similar model of healthy marriage and relationship skills and support services to interested low-income unmarried parents around the time of the birth of a child. While many unmarried parents live together when their children are born, their relationships are often tenuous and most end within a few years of the child’s birth. Research suggests that children do better when raised by both of their parents in healthy environments. The BSF program model included curricula-based group workshops on relationship skills; individual support from family coordinators; and assessment and referral to other needed services. The key question addressed through the BSF evaluation is whether the interventions improved the quality of unmarried parents’ relationships, increased the likelihood that they remained together, and improved the well-being of children. This report presents final impact results from data collected 36 months after couples enrolled in the study. A separate technical supplement details the analytic approaches and includes additional analyses.