Objective This study aimed to compare emergency medical services (EMS) and police utilization trends, epidemiology, and emergency department (ED) outcomes between pediatric patients with mental or behavioral health (MBH) emergencies and those with non-MBH concerns transported to a large children's hospital system. Methods This was a retrospective cohort study of patients aged 5 to 18 years transported via EMS and police to two EDs affiliated with a children's hospital from January 2012 through December 2020. Data were abstracted from electronic hospital records. Encounters for MBH emergencies were identified using diagnostic codes and chief complaints. Trends of EMS and police transports of patients with MBH emergencies were examined. Patient demographics and ED outcomes were compared between children presenting with MBH emergencies and those with non-MBH concerns. Results During the 9-year study period, out of 40,663 transports to the EDs, 36,137 (89%) arrived via EMS, and 4,526 (11%) arrived via police. A total of 10,250 (28.4%) EMS transports were for MBH emergencies. The volume of patients transported by EMS for MBH emergencies increased by 1.4% per year (P < 0.01) with no significant change in total EMS patient volumes. Patients with MBH emergencies transported by EMS were more likely to be older, female, of White race, and publicly insured; require restraint in the ED; and be admitted (P < 0.001). Of police transports, 4153 (91.8%) were for MBH emergencies, with no statistical change in the proportion of police transports that were for MBH emergencies. Police-transported MBH patients compared to non-MBH police-transported patients were more likely to be younger, female, and of White race (P < 0.001); 8.7% required mechanical/physical restraints in ED, 6.7% required pharmacologic restraint medications in ED, and 53% were admitted. Conclusions The proportion of pediatric transports for MBH emergencies by EMS is rising and comprises the majority of police transports. Distinct from non-MBH pediatric patients transported, MBH patients necessitate significant ED resources, including ED-administered restraints and admission, highlighting their unique burden on the prehospital and ED systems.