Research has clearly demonstrated a link between marital conflict and child adjustment. Yet few studies have explored the impact of early exposure to constructive marital conflict and the transition to adolescence using a longitudinal study design that does not involve retrospective data, and especially few studies have attempted to identify pathways and mediators accounting for the positive effects of constructive conflict. Additionally, few studies have examined how family processes change overtime, as well as how those changes impact other family systems and child adjustment. This study sought to answer three main questions: first, to understand the change trajectory of constructive and destructive marital conflict, as well as warm parenting and family expressiveness; second, to understand how changes in constructive and destructive marital conflict impact adolescent social adjustment; and third, to explore how changes in warm parenting and family expressiveness may act as intervening variables between changes in marital conflict and positive adolescent outcomes. A longitudinal sample over eight years, from early childhood into early adolescence was utilized. Latent growth curve modeling results suggest that constructive and destructive marital conflict, as well as mothers’ and father’s warmth and family expressiveness all decline overtime. Additionally, initial levels of positive family expressiveness act as intervening variables between initial levels of destructive marital conflict and adolescent closeness in friendships, and initial levels of mothers’ warmth act as intervening variables between initial levels of constructive marital conflict and adolescent prosocial behavior. Results highlight the need to take a family systems approach to understanding adolescent development, as well as demonstrate the importance of positive family relations for adolescent development.