Our findings show that insufficient sleep (IS) and circadian delay (CS) are common findings in children under evaluation for narcolepsy, and are under-reported by parents. Contrary to our hypothesis, IS and CS were not more common in children who met MSLT criteria for a primary hypersomnolence disorder than those who did not. Nevertheless, actigraphy has added value in the identification of other sleep disorders that can mimic or exacerbate the hypersomnolence of narcolepsy or idiopathic hypersomnia.