OBJECTIVE: To describe social and ethnic group differences in children's use of healthcare services in England, from 2007 to 2017. DESIGN: Population-based retrospective cohort study. SETTING/PATIENTS: We performed individual-level linkage of electronic health records from general practices and hospitals in England by creating an open cohort linking data from the Clinical Practice Research Datalink and Hospital Episode Statistics. 1 484 455 children aged 0-14 years were assigned to five composite ethnic groups and five ordered groups based on postcode mapped to index of multiple deprivation. MAIN OUTCOME MEASURES: Age-standardised annual general practitioner (GP) consultation, outpatient attendance, emergency department (ED) visit and emergency and elective hospital admission rates per 1000 child-years. RESULTS: In 2016/2017, children from the most deprived group had fewer GP consultations (1765 vs 1854 per 1000 child-years) and outpatient attendances than children in the least deprived group (705 vs 741 per 1000 child-years). At the end of the study period, children from the most deprived group had more ED visits (447 vs 314 per 1000 child-years) and emergency admissions (100 vs 76 per 1000 child-years) than children from the least deprived group.In 2016/2017, children from black and Asian ethnic groups had more GP consultations than children from white ethnic groups (1961 and 2397 vs 1824 per 1000 child-years, respectively). However, outpatient attendances were lower in children from black ethnic groups than in children from white ethnic groups (732 vs 809 per 1000 child-years). By 2016/2017, there were no differences in outpatient, ED and in-patient activity between children from white and Asian ethnic groups. CONCLUSIONS: Between 2007 and 2017, children living in more deprived areas of England made greater use of emergency services and received less scheduled care than children from affluent neighbourhoods. Children from Asian and black ethnic groups continued to consult GPs more frequently than children from white ethnic groups, though black children had significantly lower outpatient attendance rates than white children across the study period. Our findings suggest substantial levels of unmet need among children living in socioeconomically disadvantaged areas. Further work is needed to determine if healthcare utilisation among children from Asian and black ethnic groups is proportionate to need.