Sleep problems are very common in children with ADHD, with a prevalence rate as high as 73%, and often pose significant challenges and stress to the families. Sleep problems in ADHD children are strongly associated with the exacerbation of daytime symptoms, impaired physical health, and poor parental mental health. The present study is a randomised controlled trial to compare the effects of a parent-based sleep intervention for children with ADHD (aged 6-12). Eligible participants will be randomised to either intervention (two face-to-face consultation sessions and one follow-up phone call) or waiting-list control condition. Assessments will be conducted at pre-treatment (baseline), one-week after the intervention (post-treatment), and 3 months after the intervention.