We employed an autoregressive modelling technique with data from the Québec Longitudinal Study to prospectively examine the developmental impact of family transition on behaviour while controlling for predivorce and preremarriage effects. Teachers rated children's anxious, hyperactive, physically aggressive, oppositional, and prosocial behaviour every 2 years from kindergarten through to the end of elementary school. Once individual and parental characteristics and antecedent family events were controlled, children who experienced parental divorce before age 6 exhibited comparatively more behavioural disturbance than their peers whose parents divorced later. With the exception of a protective effect on hyperactive behaviour, remarriage did not have a significant impact on children's behaviour when the legacy of divorce was controlled. Although the results suggest that children of divorced parents show difficulty in many areas of functioning, the effects of family transition on behavioural development were dependent on the child's age and the specific behavioural dimension assessed. Compared to other points in development, early childhood divorce was associated with long-term increases in anxious, hyperactive, and oppositional behaviour during later childhood. The effects of divorce on children's fighting were short-lived. Unlike previous prospective studies that suggest predivorce effects, we did not observe behavioural disturbance prior to divorce or remarriage.