Children's understanding of marital conflict and the marital relationship was investigated in 60 children of 5, 7, and 9 years old. Age differences were hypothesized in four areas of children's understanding of marital conflict and the marital relationship, based on the development between 5 and 9 years of age of children's abilities to (a) analyse complex sequences of behavior in terms of the mental states of protagonists and (b) integrate multiple social roles. The four areas investigated were: conceptions of marital conflict, conflict resolution, family triangulation, and integration of the spousal and parental roles. Children were read stories involving family interactions. Open-ended questions were asked about their understanding of these interactions and a coding scheme was devised that reflected theoretical concepts. Nine-year-olds differed from 5-year-olds on all aspects of their understanding of marital conflict and the marital relationship, and 7-year-olds showed levels of understanding between 5- and 9-year-olds. Younger children were less likely than older children to explain marital conflict in terms of the divergent goals of each parent, to understand conflict resolution as dependent on one person changing their beliefs or goals, to understand that parents were simultaneously spouses and parents and to understand the nature of triangulation. Marital conflict is interpreted very differently by children of different ages.