The preservation and maintenance of sibling relationships in child welfare settings have begun to come to the forefront of practice and policy considerations. While past research on families coming into contact with the child protective services system has largely focused on the parent–child relationship, an emerging body of literature indicates that the relationship between brothers and sisters cannot be ignored. This paper highlights recent and historical trends in the literature on siblings in foster care, reviews some of the legal issues surrounding conjoint sibling placement, proposes a constitutionally protected right of association among siblings in out-of-home care, and explores the multiple and complex methodological challenges facing researchers in this area.