Associations between marital quality, maternal emotional expressiveness and children's sibling relationships were examined in a sample of 64 seven-year-olds and their mothers. Mothers reported on the quality of their marital relationships, and children rated the quality of their sibling relationships. Mothers and children provided data on maternal emotional expressiveness. Results indicated that marital dissatisfaction was associated with hostile and rivalrous sibling relationships and with maternal negative emotional expressiveness. Mothers' negative emotional expressiveness was correlated with hostile and rivalrous sibling relationships, and maternal positive emotional expressiveness was associated with affectionate sibling relationships. Maternal emotional expressiveness mediated the links between the marital relationship and sibling hostility and rivalry.