Parenting practices have been previously linked to childhood externalizing behaviour. However, little attention has been given to the potential effect of individual personality differences among children on this relation. The current study assesses the additive effects of children's personality characteristics and explores the moderating effects of children's personality on relations between parenting practices and childhood externalizing behaviour using a proportional stratified sample of 599 nonclinical elementary-school-aged children. Multiple regression analyses reveal that in the mother data as well as in the father data, dysfunctional parenting and the children's personality characteristics Benevolence, Conscientiousness, and Extraversion were directly related to outcomes consistent with an additive model of their effects. Significant interactions indicate that children with low scores on Benevolence who were exposed to overreactive discipline practices exhibited higher levels of externalizing behaviour. Children characterized by low scores on Conscientiousness who were exposed to coercive parenting behaviour showed elevated levels of externalizing behaviour. These results suggest that integrating children's personality characteristics within parenting models can improve the understanding of the aetiology of childhood externalizing problem behaviour. The implications of such integrations for intervention are discussed. Copyright © 2002 John Wiley & Sons, Ltd.