Aims: Sleep problems in Australian children are common and consequential but have not been investigated in Australian Aboriginal or Torres Strait Islander (indigenous) children. This study compares sleep in indigenous and non-indigenous children and investigates potential effects on school performance and daytime behaviour. Methods: Subjects included 25 indigenous and 25 non-indigenous children (mean standard deviation (SD) age = 8.8 (1.4 years), range 7–11.11 years), in six Northern Territory primary schools. Parents completed the Sleep Disorders Scale for Children which produces a T-score (mean = 50 (SD = 10)) for behavioural sleep disorders, sleep disordered breathing, parasomnias, excessive daytime sleepiness and night sweating. Behaviour and school grades were assessed with the parent-reported Child Behaviour Checklist. Results: Behavioural sleep problems of initiating and maintaining sleep, or parasomnias were commonly reported by both groups (24–40%), with indigenous children under 9 years reporting the most problems. No between-group differences were found in school performance. Significant relationships between sleep quality and behaviours were found, particularly for indigenous children. Conclusions: These data suggest that substantial numbers of Australian children – more than one third in this pilot sample – may suffer from significant sleep problems. To the extent that sleep problems may impair prefrontal cortical function, emotional regulation, and control of behaviour, confirmation of current findings could have particular import for indigenous children.