Purpose: The study investigated whether sibling relationships influenced the outcomes of a sample of adoptive placements in England and Wales that had broken down postorder or were in crisis. Method: The study used secondary analysis drawing on in-depth interviews with 41 families who had experienced an adoption disruption and 42 families who described the adoptive placement as being in crisis in England and in Wales. The families contained 214 adopted and birth children. Results: Siblings placed together were statistically more likely to disrupt in comparison with sequential placements. Only 18 of the 83 families described normal sibling relationships. Placements intended to maintain sibling relationships had not done so. Conclusion: Assessments need to pay more attention to sibling dynamics. Children's relationships might be better supported by separate placements with planned contact. Interventions are needed to improve sibling relationships.