One of the most devastating disorders associated with puberty is depression. Understanding the emergence of depression during puberty, as well as tracing its development might aid in more effective preventive and therapeutic interventions. The purpose of this study was to explore the impact of menarche in girls and voice-change in boys on changes in depression, self-esteem, body image, and externalizing behavior problems and explore the effects of factors that might either exacerbate or buffer the negative impact of physical pubertal change on psychological well-being. The study focused on Mexican early adolescents in Mexico City in order to expand the knowledge base of early adolescence in diverse cultures. Study participants consisted of 951, fifth, sixth, and seventh grade Mexican students. To evaluate the effect of pubertal change longitudinally on girls’ and boys’ depressive symptomatology, body image, self-esteem, and externalizing behavior problems, multivariate general linear models with repeated measures were tested. The major finding of this study was that the acute experience of menarche, not the timing, adversely affected Mexican adolescent girls’ psychological well-being, specifically in terms of depressive symptomatology. The voice change in Mexican boys did not appear to adversely affect psychological well-being other than a minimal and temporal readjustment. Tables and references