The increasing use of digital media and devices by children has led to growing concerns that spending time online without sufficient guarding is having negative effects on their health and wellbeing. In this Viewpoint, we argue that children’s use of digital technologies and engagement in digital environments should be recognised as important determinants of their health and that a public health approach is required to protect children from digital harms. Drawing on lessons from well-established approaches to address other public health challenges, we summarise three groups of public health interventions that can help delay media use among very young children, reduce digital media use among children of all ages, and mitigate any harmful consequences of children’s digital media use.