Sleep duration and disturbances in typically developing (TD) children have been found to vary across countries. Given the impact of culture on sleep patterns in TD children, it is also necessary to examine the impact of culture on sleep patterns in children with atypical development. However, previous studies have often relied only on parent reports of children’s sleep. Hence, the present study conducted a cross-cultural comparison of sleep duration and disturbances of school-aged TD children and autistic children in the UK and South Korea (hereafter Korea) using both subjective and objective sleep measurements. Cultural differences were observed in both actigraphy measures and parent reports of children’s sleep duration and disturbances. Both TD children and autistic children in Korea had a later bedtime, later getting up time and shorter nocturnal sleep duration than their peers in the UK (p < .05). Furthermore, greater parent-reported sleep disturbances were reported in TD children in Korea compared to TD children in the UK and in autistic children in the UK compared to autistic children in Korea. Correlational analyses indicated that most parent-reported measures of children’s sleep did not significantly correlate with objective measures and child reports, suggesting that studies on children’s sleep can benefit by collecting data from multiple sources. Taken together, these findings suggest a cultural influence on sleep duration and disturbances of both TD children and autistic children. This study raises questions for further research to identify factors underlying cultural differences in children’s sleep duration and disturbances.