Psychoendocrine research on stress in healthy children and adolescents is entering its fifth decade. Forty some years ago, the questions we were asking about the role of stress hormones in human development, most notably, cortisol, were quite different, and much more humble, than the ones we are asking today. From these humble beginnings, human developmental psychoendocrine research has burgeoned, until today the search terms "cortisol and children and emotion" returns over 11,000 citations. This review will not cover the entire field of work on this system in pediatric populations. It will focus for the most part on physically healthy children. Where psychiatric disorders are discussed, it will be within the context of the role of the hypothalamic-pituitary-adrenocortical (HPA) axis in transducing early life stress (ELS) into psychopathological outcomes. What will be covered in some detail is work on parent-child relationships as regulators of the HPA axis in childhood and adolescence, child care, peer relations, and early life stress (ELS) and its effects of stress reactivity. (PsycInfo Database Record (c) 2022 APA, all rights reserved).