Infant and early childhood mental health—to the uninitiated, this phrase often conjures up thoughts of a 12-month-old baby on a therapy couch, being asked to “tell me about your childhood.” However, for those of us working with babies and young children, infant and early childhood mental health is a concept paramount to understanding and supporting infants and young children as they develop, learn, and grow across the social, emotional and behavioral health domains. The mental health of our youngest citizens encompasses these areas of growth, as well as the relationships they build with their caregivers as their brains rapidly develop across the first five years of life.