In a 3-wave longitudinal study, the authors tested hypotheses regarding children's influence on the marital relationship, examining relations between interparental discord and children's negative emotional reactivity, agentic behavior, dysregulated behavior, and psychosocial adjustment. Participants were 232 cohabiting mothers and fathers who completed questionnaires and a marital conflict resolution task. Consistent with theory, interparental discord related to children's negative emotional reactivity, which in turn related to children's agentic and dysregulated behavior. Agentic behavior related to decreases in interparental discord, whereas dysregulated behavior related to increases in discord and elevations in children's adjustment problems. Person-oriented analyses of agentic and dysregulated responses indicated distinct clusters of children linked with meaningful individual differences in marital and psychosocial functioning. Results are discussed in terms of possible mechanisms of child effects, such as increased parental awareness of children's distress potentially leading to reduced marital conflict.