Indices of marital discord and mother-child affective processes were used to predict levels of negativity children displayed with unfamiliar peers. Thirty-nine mothers and their 5-year-olds were observed with 5-7 other mother-child dyads during a 30-minute free play session. Mother and child negativity were coded and two types of marital discord were assessed via mother self-report: affiliative discord (e.g., distress due to the lack of affiliative behaviors in the marriage) and instrumental discord (e.g., disagreements about the accomplishment of marital tasks, such as finances, time management, and goal setting). Affiliative discord was found to relate to the child's negativity with unfamiliar peers, but instrumental discord was not. Furthermore, maternal negativity moderated the link between marital discord and child's negativity with peers, such that high levels of affiliative discord combined with heightened maternal negativity was associated with child negativity. Practical implications are discussed.