Measuring health inequalities is essential to inform policy making and for monitoring implementation to reduce avoidable and unfair differences in health status. We conducted a geospatial analysis of child mortality in Iran using death records from the Ministry of Health and Medical Education from 2016 to 2018 stratified by sex, age, province, and district, and household expenditure and income survey data from the Statistical Center of Iran collected in 2017. We applied multilevel mixed-effect models and detected significant inequality in child mortality and the impact of socioeconomic factors, especially household income. We advocate for using mortality rate for young children (< 5 years old) as an indicator for assessing the impact of interventions to reduce inequalities among various socioeconomic groups. We also recommend to design and implement comprehensive and longitudinal data collection systems for accurate, regular, and specific monitoring of health inequalities.