Several theoretical models of child development have posited the spread of conflict within families; however, few researchers have studied this process in association with relationships children have with teachers and peers at school. The present study examined the direct, additive, and interactive contributions of interparental, parent–child, and sibling conflict in relation to teacher–child and child–peer conflict in a sample of 117 low-income boys from ages 3.5 to 6 years. Overall, the results suggest that while conflict in any one dyadic family relationship is only modestly associated with later conflictual relationships at school, risk for conflict in relationships with teachers and peers increases when multiple forms of early family conflict are experienced. Results are discussed in terms of the development of conflict across early relationships.