Background: Children have differing utilization of emergency medical services (EMS) by socioeconomic status. We evaluated differences in prehospital care among children by the Child Opportunity Index (COI), the agreement between a child's COI at the scene and at home, and in-hospital outcomes for children by COI. Methods: We performed a retrospective study of pediatric (<18 years) scene encounters from approximately 2,000 United States EMS agencies from the 2021-2022 ESO Data Collaborative. We evaluated socioeconomic status using the multi-dimensional COI v2.0 at the scene. We described EMS interventions and in-hospital outcomes by COI categories using ordinal regression. We evaluated the agreement between the home and scene COI. Results: Data were available for 99.8% of pediatric scene runs, with 936,940 included EMS responses. Children from lower COI areas more frequently had a response occurring at home (62.9% in Very Low COI areas; 47.1% in Very High COI areas). Children from higher COI areas were more frequently not transported to the hospital (odds ratio [OR] 0.87, 95% confidence interval [CI] 0.86-0.87). Children in lower COI areas had lower use of physical (OR 1.23, 95% CI 1.13-1.33) and chemical (OR 1.41, 95% CI 1.29-1.55) restraints for behavioral health problems. Among injured children with elevated pain scores (≥7), analgesia was provided more frequently to children in higher COI areas (OR 1.73, 95% CI 1.65-1.81). The proportion of children in cardiac arrest was lowest from higher COI areas. Among 107,114 encounters with in-hospital data, the odds of hospitalization was higher among children from higher COI areas (OR 1.14, 95% CI 1.11-1.18) and was lower for in-hospital mortality (OR 0.75, 95% CI 0.65-0.85). Home and scene COI had a strong agreement (Kendall's W = 0.81). Conclusion: Patterns of EMS utilization among children with prehospital emergencies differ by COI. Some measures, such as for in-hospital mortality, occurred more frequently among children transported from Very Low COI areas, whereas others, such as admission, occurred more frequently among children from Very High COI areas. These findings have implications in EMS planning and in alternative out-of-hospital care models, including in regional placement of ambulance stations.