A system of care for abused and neglected infants and young children should adopt a comprehensive perspective, with mental health considerations systematically incorporated into policies and decisions affecting children and their families. Children age birth to 5 years have disproportionately high rates of maltreatment, with long-term consequences for their mental and physical health. Research on normal development and developmental psychopathology has shown that early development unfolds in an ecology of transactional influences among biological, interpersonal, and environmental domains. Psychologists should collaborate with other early intervention disciplines to create systems of care based on an ecological-transactional model of development that includes early mental health principles in order to serve the needs of these young children. Didactic courses, practicums, and internships in infant and early childhood mental health should become integral components of undergraduate and graduate curricula in psychology in order to build capacity to achieve this goal. Recommendations are offered for systemic change by integrating infant and early childhood mental health principles into existing systems of care for young children and their families.