Previous investigations of the longitudinal outcomes of childhood aggression, social withdrawal and likeability have relied on the reports of a single observer, or combined the results of several observers in the prediction of adult outcomes.  By comparing self and peer perceptions of childhood behaviour, the present studies proposed to clarify the nature of the relation between childhood behaviours and adult outcomes.  Four questions were examined being (1) how were childhood behaviour patterns related to adult outcomes; (2) how did self and peer perceptions compare in the prediction of adult outcomes; (3) was the relation between self and peer perspectives additive in the prediction of these outcomes; and (4) did concordance between self and peer perspectives predict adult outcomes? Data from the Concordia Risk Project were employed to determine the socioeconomic, personality, and substance abuse outcomes. Both self and peer perceptions of childhood behaviour were associated with adult outcomes, although generally, self perceptions as opposed to peer perceptions of childhood behaviours were more strongly associated with adult outcomes in women.   Including both self and peer perceptions did not have an additive effect in the prediction of adult outcomes, although there was some support for the importance of concordance in education and income outcomes. The findings suggest that self and peer perceptions of childhood behaviour each provide some unique information. Future research examining the adult outcomes of childhood behaviours may wish to consider both the gender and the behaviour being examined in designing prospective, longitudinal studies.