Relations were examined between emotional expression in the family, children's understanding of emotions as assessed in a task situation, and their social understanding as reflected in conflict management and pretend play. Results highlight the importance of taking account of both the general level of expression of negative affect in the family (which was associated with poorer performance on emotion-understanding tasks, less negotiation in conflict, and less role enactment in pretend) and the significance of children's affective state for particular interactions. Discourse about feelings (linked to later emotional understanding) was more likely when children were expressing negative affect. The pattern of such associations differed, however, in families with high or middle/low levels of emotional expression.