Children who have experienced parental separation have potentially 3 sets of parents whose relationships may impact on them: mother and former partner, mother and stepfather, and father and new partner. Children's accounts of their response to conflict between these different parental dyads were studied, in relation to the quality of their relationships with these parents assessed with child interviews and questionnaires, and to maternal reports of the children's adjustment, in a sample of 159 children growing up in different family settings. Involvement in conflict within 1 parental dyad was chiefly unrelated to such involvement in conflict between the other parental dyads. In contrast, there was evidence for "spillover" effects in relationships within families; for instance, high frequencies of conflict between parents were linked to more troubled parent?child relationships. Children were more likely to side with the parent to whom they were biologically related than with stepparents. Involvement in mother-nonresident father conflict and in mother-stepfather conflict were both associated with adjustment problems, independent of the qualities of positivity and conflict in the relationship between child and parent. Implications for views on "family boundaries" are considered.