Using a developmental systems perspective and public-use longitudinal data from participants currently in a romantic relationship at Wave 4 of the National Longitudinal Study of Adolescent Health (n = 2,970), the current study explored direct and indirect paths from parent–adolescent relationship quality to young adult intimate relationship quality. Structural equation modeling tested whether mental health (depressive symptoms and self-esteem) in the transition to adulthood mediated the association between parent–adolescent relations and young adult intimate relations. The results indicated that higher quality parent–adolescent relations predicted higher self-esteem and lower depressive symptoms during the transition to adulthood as well as higher young adult intimate relationship quality, controlling for adolescent mental health and parent–young adult relationship quality. Higher self-esteem during the transition to adulthood was associated with greater intimate relationship quality, whereas greater depressive symptomatology predicted reduced intimate relationship quality. One significant indirect path emerged: parent–adolescent relationship quality → self-esteem → intimate relationship quality.