Social support can have significant stress-preventive and stress-buffering benefits for troubledindividuals in everyday circumstances. Consequently, it is not surprising that many therapeutic andpreventive programs enlist social support to address problems of child and familypsychopathology, especially in the context of “two-generation interventions” thatseek to improve child well-being by strengthening parental functioning and parent–childrelationships. Home visitation programs are the best known of these two-generation strategies andhave become the focus of state-level and national efforts to support families and prevent harm tochildren. The conclusions of basic research studies on social support converge significantly withthe findings of evaluation studies of the impact of home visitation programs to yield importantnew insights into the conditions in which formal social support is likely to be beneficial, orineffective, in improving child and family well-being. Both basic and applied research literaturesemphasize the importance of linking formal social support to informal social networks in extendedfamilies, neighborhoods, and communities, and attending to the complex reactions of therecipients of support and the needs of support providers. These studies are reviewed andevaluated to highlight the connections between social support, developmental psychopathology,and social policy.