Background: The COVID-19 pandemic has had a profound impact on pediatric mental health, contributing to a global surge in psychiatric emergencies among children and adolescents. This study aimed to evaluate trends in pediatric emergency department (PED) visits for three key psychiatric conditions—anxiety disorders (ADs), self-injury behaviors (SIBs), and psychomotor agitation (PMA)—before and after the onset of the COVID-19 pandemic. Methods: We conducted a retrospective observational study at a tertiary pediatric hospital in Italy, analyzing all psychiatric presentations to the PED from 1 January 2018 to 31 December 2024. The data were divided into pre-COVID and post-COVID periods and included patient demographics, recurrence of visits, clinical features, hospital admissions, and pharmacological management. Diagnoses were confirmed by chart review. Results: Of 233,867 total PED visits, 1082 were due to primary psychiatric concerns. A marked increase in visits was observed postCOVID: SIB incidence rose from 3.6 to 15.1 per 10,000 visits (p < 0.0001), PMA from 9.4 to 17.8 (p < 0.0001), and AD from 17.7 to 21.6 (p = 0.018). SIB cases showed increased recurrence (from 3.4% to 27.4%, p = 0.004) and greater pharmacological intervention, whereas PMA was associated with a rise in heteroaggression (from 14.3% to 39.8%, p < 0.0001). Pharmacological treatment remained largely consistent, with benzodiazepines and neuroleptics most frequently used. The emerging use of intranasal ketamine was noted in select cases. Conclusions: This study highlights the increasing burden of pediatric psychiatric emergencies in the wake of the COVID-19 pandemic. The findings underscore the urgent need to implement standardized emergency care protocols, strengthen outpatient mental health services, and develop pediatric-specific pharmacological guidelines to improve outcomes in this vulnerable population.