Background: Sleep is instrumental for growth and development in children, making it critical to establish healthy sleep habits from the earliest years of life. Many kindergarteners (3–6 years) in China have inadequate and poor sleep, necessitating targeted interventions. This research protocol details the “Healthy Sleep” intervention that was designed to promote healthy sleep among kindergarteners in China. Methods: The “Healthy Sleep” intervention will be family-based and will support parents as change agents. The development of the intervention is based on evidence regarding correlates of sleep in young children and guided by Bandura’s social cognitive theory. A 12-month randomised controlled trial will be conducted to examine the efficacy of the intervention for promoting healthy sleep in Chinese kindergarteners and the intervention's effects on child development outcomes. A targeted sample of 160 kindergarteners and their parents will be recruited through social me