Objective: This study utilized a novel multisystem approach to investigate the effect of observed parental behavior on the relationship between biological mechanisms associated with disease processes (i.e., autonomic physiology and immune response) among their adolescent children. Method: Thirty-three adolescents (23 males), aged 11–13, and their parents participated in a laboratory session in which adolescents provided baseline measures of autonomic (sympathetic) activity, and adolescents and 1 parent participated in a laboratory based dyadic conflict resolution interaction task. This included 3 male parent/male adolescent dyads, 20 female parent/male adolescent dyads, 3 male parent/female adolescent dyads, and 7 female parent/female adolescent dyads. Approximately 3 years later, adolescents provided a salivary measure of C-Reactive Protein (sCRP) to index inflammation. Results: Analyses revealed a positive association between sympathetic activity and sCRP, as well as a moderating role of positive parental behavior in this relationship, such that the association between sympathetic activity and sCRP was greater among adolescents whose parents displayed shorter duration of positive affect. Conclusions: Overall findings indicate parental behavior may influence the association between adolescent sympathetic activity and inflammatory processes. These findings have important implications for understanding the impact of psychosocial factors on biological mechanisms of disease. (PsycInfo Database Record (c) 2022 APA, all rights reserved)