The concept of families and health is a universal issue that concerns the most diverse people, communities, and cultures. Across the world, the family, as the fundamental unit of society, is increasingly recognized as an important influence on or determinant of the collective and individual health of its members. The complex interactions within and outside the family circle shape behavior, lifestyle, relationships, perceptions, and ultimately, health capacities and health decisions. Given the family's primary roles of nurturing, caring, protecting, and rearing, it serves as an effective entry point and focus of health promotion and [Page 473]health care delivery. This entry discusses the various definitions of the family, the underlying theoretical framework and strategies of a family-based approach to health, and selected examples of family-based interventions.