The Buffering Toxic Stress (BTS) consortium included six sites in locations that varied widely in racial/ethnic composition and population density. Each site tested a promising parent-child intervention designed to supplement Early Head Start (EHS) services and prevent "toxic stress." To better understand family risk in a large and diverse EHS sample, studies gathered extensive data on family risk exposure, including demographic risk factors (single mother, unemployed, less than high school education or its equivalent, and neighborhood safety), income-to-needs ratio, household resource constraints, perceptions of economic hardship and pressure, caregiver mental health, and caregiver-reported dysfunctional parent-child interactions. Results presented here for all six sites offer context for the more targeted studies in this special issue. Average levels of family characteristics and child behavior varied by site. We also characterized associations between family characteristics, observer-rated child temperament, and child outcomes (i.e., caregiver-reported child behavior problems and behavioral sleep quality), controlling for child age; these relationships were similar across sites. Demographic risk and caregiver mental health problems were positively associated with child behavior problems, with low income-to-needs ratio and increased financial strain relating to behavioral problems in infancy and toddlerhood. Caregiver mental health problems, financial strain, and social and affect temperament dimensions were related to increased behavioral sleep problems. Dysfunctional parent-child interactions and household resource constraints did not demonstrate statistically significant associations. Findings suggest helpful targets to increase effectiveness of parent-child interventions in early childhood on behavior and sleep outcomes.