Stability and correlates of individual differences in children's relationships with their siblings between early childhood and adolescence were studied in 39 sibling dyads, using home observations and maternal interviews in the early childhood period and interviews with mothers and children at the later time points. Stability of individual differences found over the 7 years increased with age. The behavior of the other sibling in the preschool period related to both older and younger siblings' behavior at the last time point. Life events were associated with increased warmth between the children. By preadolescence, gender and socioeconomic status (SES) were related to differences in the relationship. Multiple regression showed that preschool measures of sibling interaction contributed independently of gender and SES to the variance in individual differences in positive aspects of the relationship at early adolescence.