The current emphasis on accountability and delivery of quality early childhood intervention (ECI) programs calls for the examination of outcomes and associated factors. The aim of the present study was twofold: (1) to examine changes in child and family outcomes, parental self-efficacy and perceptions of family-centered practices following participation in an ECI; and (2) to examine relationships among these variables at pre- and post-intervention. Sixty-six families of children with developmental disabilities (M = 46 months) completed measures of family outcomes, parental self-efficacy, and perceptions of family-practices at pre- and post-intervention. ECI professionals provided child outcome ratings. Significant increases in all measurement variables from pre- to post-intervention were revealed. Relationships among some child characteristics, family and child outcomes were shown, as well as associations among family-practices, parental self-efficacy, and family outcomes at each pre- and post-intervention phases. The measurement and evaluation of the relationships among child and family outcomes and program factors are critical in demonstrating the quality of ECI service delivery.