Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic and hypnopompic hallucinations. The onset of the symptoms usually occurs in childhood, and previous studies have reported an association between narcolepsy and other endocrine diseases in the pediatric population, such as obesity and precocious puberty. The incidence of overweight or obesity ranges from 25% to 74% in patients with narcolepsy type I, while precocious puberty is present in 17% of children with narcolepsy with cataplexy. However, the mechanisms involved in the association of narcolepsy with obesity and precocious puberty have not been fully elucidated yet. In this review, we aimed to discuss narcolepsy in pediatric populations, highlighting the diagnostic difficulties and the complexity of the possible mechanisms that can relate narcolepsy to precocious puberty and obesity. We also emphasized the fact that endocrine diseases must be taken into consideration in children diagnosed with narcolepsy.