OBJECTIVES: Current recommendations for healthy sleep in school-aged children are predominantly focused on optimal sleep duration (9-11h). However, given the importance of routine for circadian health, the stability of sleep/wake schedules may also be important, especially for daytime behavioral functioning. We examined the relationship between short sleep duration, sleep schedule instability and behavioral difficulties in a community sample of Australian children. METHODS: Children, aged 5-10 years (N=1622), without chronic health or psychological conditions, were recruited from primary schools in Adelaide, South Australia. A parent-report questionnaire was used to assess sleep/wake behavior. Behavioral functioning was assessed using the Strengths and Difficulties Questionnaire. RESULTS: Most children met sleep duration recommendations with approximately 5 reporting 12h. Weekly variability of bed and rise times >1h were reported in up to 50 of children. Multinomial regression analysis revealed sleep duration 60min, and bed and rise time variability >60min significantly increased the risk of scoring in the 95th percentile for behavioral sub-scales. CONCLUSIONS: Inconsistent sleep schedules were common and, similar to short sleep duration, were associated with behavioral difficulties. Considering the lack of study in this area, further research is needed for the development of new recommendations, education and sleep health messages.