ABSTRACT Those in family court proceedings are at the sharp end of a spectrum of disputes concerning their children’s upbringing. Emerging evidence shows that, regarding both public and private law, socioeconomic and health deprivation of various forms is associated with higher rates of proceedings. Discovering health and social determinants of proceedings could inform upstream interventions to support parenting, improve wellbeing, reduce conflict and adversity and prevent the need for court involvement in the first place. It could also inform measures to mitigate the adverse health effects of legal processes on vulnerable families and debates on legal aid and alternative dispute resolution in private proceedings. This ‘public health’ approach to family justice is now possible by innovations in linking whole-population, routinely collected datasets between the courts, healthcare and other services. This article explores the possibilities of combining legal and epidemiological understandings, methods and skills in researching family justice to inform practice, policy and legislative reform.