This systematic review analyses research measuring or evaluating primary health care interventions that focused on improving the mental health of Indigenous children via intersectoral service integration processes and tools. Of the eleven studies included five were conducted with Indigenous children (aged 4 to 17 years) in Australia, the remaining studies included New Zealand, Canada, Norway and/or the United States. Among thenine key strategies adopted by service integration interventions of note were: Engaging the members of the Indigenous community; Empowerment of families; Adapting interventions and care to the specific socio-cultural circumstances; and Cultural strengthening and empowerment of Indigenous children’s identity. Six factors enabling effective implementation of service integration included: Including and involving the community and stakeholders, Sensitivity to culture, including to historical background and inter-generational trauma, Multi-disciplinary and collaborative health services and Resourcing factors (e.g. funding, costs, time availability, staff/organisation capacity). The authors conclude that while the research evidence for interventions focused on improving the mental health of Indigenous children via intersectoral service integration is preliminary the findings hold potential. Importantly, the main outcomes where strategies focused on intersectoral integration were: Improvements in children’s psychosocial functioning, stress management, and individual empowerment; Improvements in health service access and use; Empowerment of both families and communities; and Increased links and collaboration between the community and health services. The authors identify the need for further research, particularly to incorporate Indigenous voices in evaluation, help clarify impact, and to evaluate costs.