Socioeconomic inequality and child maltreatment have not been studied using the concentration index as an indicator of inequality. The study aimed to assess the association of child maltreatment with socioeconomic status among schoolchildren in Qazvin province, Islamic Republic of Iran. In this cross-sectional study a questionnaire based on the ISPCAN Child Maltreatment Screening Tool–Children’s Version and the Juvenile Victimization Questionnaire was filled by 1028 children aged 9–14 years, selected through multistage stratified random sampling. The concentration indices for economic inequality were –0.086 for any type of child maltreatment and –0.155, –0.098 and –0.139 for the physical, psychological and neglect subtypes of maltreatment respectively. The number of children and the economic status of the family also showed a significant association with child maltreatment in all 3 subtypes. Appropriate planning for effective interventions for at-risk children of lower socioeconomic status should be considered by the relevant decision-makers.