A family systems perspective directs attention to the potentially different experiences and perspectives of family members. This study examined parents' differential treatment (PDT) of siblings, discrepancies between parent and youth reports of PDT, and their links with relationships between adolescents and their mothers and fathers across three years. Participants were first- (Time 1 M age = 15.71, SD = 1.07) and secondborn (Time 1 M age = 13.18, SD = 1.29) siblings from 381, predominately white, working and middle class families. Analyses revealed that siblings' perceptions of being favored predicted less conflict with and greater warmth from both mothers and fathers, primarily for secondborn adolescents. Larger discrepancies between maternal and youth reports of differential affection were linked to more maternal conflict and less warmth for firstborns. These findings may suggest a hierarchy within families: parents may serve as referents for firstborns and firstborns as referents for secondborns.