This study investigated the effectiveness of the Triple P Programme to reduce stealing behaviour in three preadolescent children. Using behavioural monitoring and self-report questionnaires, outcome measures included stealing behaviour, parenting practices, parenting efficacy, and parental mental health. A measure of change was also included to identify change points in the therapeutic process. Results suggest that parent training is effective in the reduction of stealing behaviours, as positive changes were found across all the measures employed. This early intervention has the potential to disrupt an antisocial developmental trajectory for children who steal. Limitations of the study and directions for future research are discussed.