As support for intervening early in the lives of vulnerable children has risen in the United States in recent years, so has interest in home-visitation programs. Home visitation is increasingly recognized for its potential to foster early child development and competent parenting, as well as to reduce risk for child abuse and neglect and other poor outcomes for vulnerable families. This paper provides a discussion of several aspects of home-visitation programs that warrant further development and evaluation, including the powerful role of context in determining program outcomes, as well as the impact of other factors, including service dosage, levels of family engagement, and characteristics of home visitors. The importance of more accurately understanding and measuring risk and engaging family members beyond the mother-child dyad is also discussed. Recommendations are made for making improvements in all of these areas, in order to strengthen home-visitation programs and produce better outcomes for the children and families they serve. Aspects of Nurse Family Partnership and Early Head Start, two widely replicated and rigorously evaluated programs, are highlighted to demonstrate how the issues discussed here are likely to affect service delivery and program outcomes. The multiple challenges inherent in replicating and evaluating home-visitation programs that are truly responsive to the needs of a wide array of families with young children are examined. This discussion concludes with a call to expand and improve methods for evaluating these programs, and to view home visitation as a component of a comprehensive system of child and family supports, rather than as a stand-alone model of intervention.