Abstract Introduction Narcolepsy is a disabling neurological disorder characterized primarily by excessive daytime sleepiness (EDS), cataplexy, hypnagogic hallucinations, sleep paralysis, rapid eye movement (REM) behavior disorder (RBD) and disturbed nocturnal sleep. Over 50% of children with narcolepsy are obese. Metabolic syndrome (MetS), a constellation of disturbances associated with obesity, is increasingly seen in narcolepsy. A higher prevalence of MetS was revealed both in adults and children with narcolepsy. The objective of the present study was to compare clinical and sleep characteristics in children with narcolepsy with different components of MetS to clarify the mechanisms in MetS in these children. Methods This retrospective study included 58 children with narcolepsy. Data on blood pressure, High density lipoprotein (HDL) cholesterol, triglyceride, glucose, insulin and anthropometry (height and weight) were collected. MetS was defined when ≥3 of the following criteria were met: (1) Body mass index (BMI) ≥IOTF-30, (2) Blood pressure ≥90th percentile, (3) HDL-C ≤0.4 g/L, (4) Triglycerides ≥1.3 g/L, (5) homeostasis model assessment of insulin resistance (HOMA-IR) ≥75th percentile. Then, clinical and sleep characteristics were compared in groups with different MetS components. Results A total of 17 % of children with narcolepsy had MetS including 79% with high HOMA, 26% with high BMI, 24% with low HDL cholesterol and 12% with high triglycerides, but no patient with high blood pressure. 58% of the patients without obesity had at least 1, 2 or ≥3 MetS risk factors (78%, 15% and 6%, respectively). 55% of them were overweight. In children with narcolepsy with at least two MetS risk factors, there was a higher proportion of night eating, a lower percentage of N3 sleep, a higher arousal index, a shorter mean sleep latency and more sleep onset REM periods (SOREMPs) compared to patients with fewer MetS risk factors. Conclusion Altered sleep architecture and eating behavior are closely associated with risk factors of MetS in children with narcolepsy, even without obesity. We recommend to evaluate MetS risk in all children with narcolepsy to prevent complications such as type 2 diabetes and cardiovascular outcomes. Support (If Any)