What is already known about this topic? Melatonin is regulated by the Food and Drug Administration as a dietary supplement and is a widely available over-the-counter sleep aid for adults and children. What is added by this report? During 2012–2021, the annual number of pediatric ingestions of melatonin increased 530% with a total of 260,435 ingestions reported. Pediatric hospitalizations and more serious outcomes also increased, primarily because of an increase in unintentional melatonin ingestions in children aged ≤5 years. What are the implications for public health practice? Increasing use of over-the-counter melatonin might place children at risk for potential adverse events. Public health initiatives should focus on raising awareness of increasing melatonin ingestions among children and on preventive measures to eliminate this risk.