The central aim of this paper is to explore whether parental separation and divorce influence children's experiences of the sibling relationship. In addressing this research aim, the paper draws on the first wave data from a longitudinal study of sibling relationships and adolescent adjustment to parental divorce. Participants include the adolescent children and their parents from 137 divorcing families, and from a comparison sample of 165 intact families. Adolescents reported on the quality of their relationship with their siblings by filling in questionnaires, and by participating in a semi-structured interview. Adolescent children from separating and divorced families were significantly more likely than children from continuously married (or intact) families to have affect-intense sibling relationships-that is, relationships characterised by high levels of both hostility and warmth. Adolescents related these aspects of the sibling relationship to their experiences of the separation and divorce of their parents, particularly the degree of conflict between parents and the absence of a father in the children's day-to-day lives. Results are discussed in terms of the role of the sibling relationship in supporting children through parental separation and divorce.