Child development and adaptation are best understood as biological and psychological individual processes occurring within the context of interconnecting groups, systems, and communities which, along with family, constitute the child's social ecology. This first of two articles describes the challenges and opportunities within a child's social ecology consisting of Micro-, Meso-, Exo-, and Macrosystems. The parent-child relationship, the most salient Microsystem influence in children's lives, plays an influential role in children's reactions to and recovery from disasters. Children, parents, and other adults participate in Mesosystem activities at schools and faith-based organizations. The Exosystem--including workplaces, social agencies, neighborhood, and mass media--directly affects important adults in children's lives. The Macrosystem affects disaster response and recovery indirectly through intangible cultural, social, economic, and political structures and processes. Children's responses to adversity occur in the context of these dynamically interconnected and interdependent nested environments, all of which endure the burden of disaster Increased understanding of the influences of and the relationships between key components contributes to recovery and rebuilding efforts, limiting disruption to the child and his or her social ecology A companion article (R. L. Pfefferbaum et al., in press) describes interventions across the child's social ecology.