Introduction Recognising the connection between country-level social determinants of health, and child unintentional injury mortality can contribute to better resource allocation for child safety. This cross-sectional country-level study aims to investigate such a link where the role of income inequality (Gini Index) is examined alongside education expenditure, current health expenditure and gross national income (GNI) per capita.

Methods A total of 49 high-income countries were studied, using the WHO Global Health Estimates 2016, the World Bank’s World Development Indicators for education and GNI per capita, and the standardised world income inequality database to compile estimates of child unintentional injury mortality rates and selected socioeconomic characteristics.

Results A wide range of childhood mortality rates from unintentional injury was observed (1.3–10.0 deaths per 100 000 children). Such risk is strongly associated with income inequality (0.50), GNI per capita (–0.35) and education expenditure (–0.01) (mediated by income inequality). No association was found to current health expenditure. The results explain 52% of the variance in child unintentional injury mortality.

Conclusions In countries with higher overall economic activity and lower-income inequality, child mortality from unintentional injuries is lower. Allocation of education expenditure is one contributor to reducing income inequality; other factors need further exploration.