--- - |2+ Background Anxiety disorders are one of the most common mental illnesses in children and associated with high healthcare utilization. We aimed to estimate 2‐year cumulative incidence of mental health–related hospitalizations, treated self‐harm, and emergency room (ER) visits in children newly diagnosed with anxiety disorders and, for context, in children without anxiety disorders. Methods We identified commercially insured treatment naïve children (3–17 years) with a new office‐based anxiety disorder diagnosis (ICD‐9‐CM) from 2005–2014 in the MarketScan claims database. We followed children for up to 2 years after diagnosis for the first of each event: mental health–related hospitalization, inpatient, treated self‐harm, and ER visits (any, anxiety‐related, injury‐related). Children without anxiety diagnoses were included as comparators, matched on age, sex, date, and region. We estimated cumulative incidence of each event using Kaplan–Meier analysis. Results From 2005–2014, we identified 198,450 children with a new anxiety diagnosis. One‐year after anxiety diagnosis, 2.0% of children had a mental health–related hospitalization, 0.08% inpatient, treated self‐harm, 1.4% anxiety‐related ER visit, and 20% any ER visit; incidence was highest in older children with baseline comorbid depression. One‐year cumulative incidence of each event was lower in the comparison cohort without anxiety (e.g., mental health–related hospitalizations = 0.5%, treated self‐harm = 0.01%, and ER visits = 13%). Conclusions Given the prevalence of anxiety disorders, 2‐year incidence estimates translate to a significant number of children experiencing each event. Our findings offer caregivers, providers, and patients information to better understand the burden of anxiety disorders and can help anticipate healthcare utilization and inform efforts to prevent these serious events. - Depression and Anxiety, EarlyView.