The present pilot study evaluated the efficacy of the Level 4 Group Positive Parenting Program (Triple P) with Hong Kong Chinese parents who had a child with attention deficit/hyperactivity disorder (ADHD), using a randomised controlled trial design. It was a mixed research method involving quantitative measurement and semi‐structured focus group. Participants were randomly assigned to Triple P (n = 8) or control group (n = 9) and completed measures on child disruptive behaviours, sense of parenting efficacy and satisfaction, family stress and service needs. Outcomes were assessed at pre‐, post‐, and 3‐month follow‐up. A focus group was also conducted with the participants in the intervention group upon the programme completion. Compared with the control group, the intervention group reported a significant reduction in intensity of child behaviour problems and a significant increase in parenting efficacy at post‐intervention. The gain in reducing intensity of child disruptive behaviours maintained to 3 months after the completion of programme. Qualitative data suggested the three key elements to help both parents and children get positive changes: understanding and empathy, emotional control, and persistence in applying positive parenting strategies. The results partially provided preliminary evidence supporting the efficacy of Triple P in reducing child behaviour problems for ADHD in Chinese society.