Abstract Background Systems thinking has emerged as a promising approach to addressing complex public health issues. For children, the focus of the approach has been on single outcomes e.g. obesity, rather than addressing the broad range of inequalities in health outcomes. We report on an approach to developing a system-oriented perspective on the determinants of inequalities in child health and wellbeing in English local authorities. Methods Qualitative group concept mapping workshops (a 'soft' system science approach) were held in two contrasting English local authorities with a range of stakeholders: professionals (N = 35); children and young people (N = 33) and carers (N = 5). Initial area maps were refined using data from qualitative interviews with professionals (N = 16) and resulting maps reviewed and validated by expert stakeholders in each area (N = 9; N = 35). Commonalities between two area-specific system maps (and removal of locality-specific factors) were used to develop a map that could be applied in any English local area. Two rounds of online consultation (N = 21; N = 8) and qualitative interviews (N = 12) with experts in public health, local governance and systems science refined the final system map displaying the determinants of child health inequalities, and give insight into its potential utilisation. Results The process created a map of over 150 factors influencing inequalities in health outcomes for children aged 0-25 years at the local area level. The system map has six domains; physical environment, governance, economic, social, service, and personal. Conclusions To our knowledge this is the first study taking a systems approach to addressing inequalities across all aspects of child health. Group concept mapping can support systems thinking at the local level. The resulting system map illustrates the complexity of factors influencing child health inequalities and is a useful tool for strategy development, action prioritisation and systems evaluation planning. Key messages Group concept mapping can be successfully applied to facilitate a systems approach to child health inequalities at the local area level. Mapping the local child health system highlights complex relationships between physical, social, personal, service, governance and economic factors which influence inequalities and health outcomes.