Parents raising a child with significant developmental challenges are profoundly aware of the often sustained impact of that child's special needs upon their other children. Supported by recent research on siblings of developmentally challenged children, clinicians are advocating family-based interventions that take into account the needs of siblings. This article reviews the experience of siblings who live with brothers or sisters diagnosed with pervasive developmental disorder or mental retardation. Contributions from research on typical siblings are drawn upon when appropriate. Six domains of the sibling experience are identified. These domains explore relational shifts within sibling relationships and through the expectable differential parental treatment of each child. Shifts considered in this review include the interrelationships with the extended family, peers, and friendships, all of which contribute to shaping the meaning that siblings give to living with developmentally challenged brothers or sisters across time.