In this article, I discuss the reasons for my interest in sibling relationships, and showcase studies on sibling relationships in adolescence carried out with my colleagues and students, in the context of the broader literature on sibling relationships. Our studies have focused on a number of important issues concerned with sibling relationships. First, I report on the associations between sibling relationships and other family relationships and the ways that the various family relationships affect each other. Second, I report a study of sibling relationships in the context of parental separation and divorce and show that sibling relationships in these families are more likely to be high in both warmth and hostility than is true for relationships in 2-parent families. Third, I report on several data sets showing an association between the quality of sibling relationships and adolescent adjustment and the link between differential parenting, adolescent adjustment, and the quality of the sibling relationship. Fourth, I report on a study of comparison and competition in sibling relationships and the associations between sibling relationship quality and reactions to being outperformed by a sibling. Finally, I discuss possible future directions for research on sibling relationships, including the importance of multimethod studies and a longitudinal perspective.