the population-based incidence of emergency medical service treated out-of-hospital cardiac arrest in children. Data Extraction: Two reviewers independently screened studies for eligibility and extracted data. Risk of bias was assessed using the JBI Critical Appraisal Checklist for Prevalence Studies. Data Synthesis: We summarized incidence rates in the overall population and in our prespecified subgroups in a meta-analysis using a random-effects model. Four thousand seven hundred eleven studies were screened with 50 finally included in our analysis including data from 18 countries (17 high-income and one upper-middle-income). Thirty-seven thousand six hundred eighty-one cardiac arrest incidents, across a total follow-up time of 547,267,107 person-years, were included in our primary analysis. Meta-analysis generated a pooled incidence rate estimate of 5.56 out-of-hospital cardiac arrest incidents in all children in the included populations, per 100,000 person-years (95% CI, 4.54–6.58;