The model tested posits a direct influence of parental attachment on psychological health and self-esteem, while the influence of peer attachment on psychological health is mediated by self-esteem. Study 1 consisted of a cross-sectional analysis of 1,998 Norwegian high school students. A questionnaire booklet contained items that measured depression, self-esteem, parental attachment, peer attachment, and perceived problems. With some modifications, the findings provided a satisfactory fit with the proposed model. Study 2 replicated study 1 with a sample of 358 Australian high school students (ages 15-18). A multi-sample analysis found no significant differences for the model in explaining the findings for the two studies. Study 3 was another replication that used alternative measures of the constructs with a sample of 345 Australian high school students (ages 15-19). The major finding from all three studies is that the role of peer and parental attachment in determining psychological health is mediated primarily by self-esteem. Thus, the primary role of attachment relationships is apparently the bolstering of self-worth rather than directly influencing psychological symptoms, notably depression. Attachment relationships with parents and peers were found to have additive and complementary roles rather than competitive roles in producing psychological well-being during adolescence. Suggestions are offered for future research in this area. 10 tables, 4 figures, and 72 references