<p>Purpose<br/>Impaired sleep has been reported to be a consequence of overweight/obesity. However, sleep-disrupting behaviour that tend to coexist with overweight/obesity are also independent risk factors for impaired sleep such as night-eating, alcohol use, insufficient physical activity (PA), electronic device use and stress/affective distress. Thus, it is unclear whether night-eating and measures of body fatness will still predict sleep quality once concurrent behaviour and affective state are taken into account.</p> <p>Methods<br/>Online questionnaires asked participants about sleep quality, night-eating, alcohol use, electronic device use and stress/affective distress at T1 (baseline) and T2 (3-months later). Height, weight and waist and hip circumference was measured at T1 and objective physical activity (PA) was assessed over 24-hours (using actigraphy) in 161 participants at T1 and T2.</p><p>Results<br/>At T1, night-eating was related to poorer subjective sleep quality, longer sleep onset latency, lower sleep efficacy, more sleep disturbances and daytime dysfunction and obesity category was related to daytime dysfunction after controlling demographics and covariates. At T2, high BMI predicted lower sleep efficacy after controlling T1 sleep components, demographics and covariates.</p><p>Conclusion<br/>Night-eating and obesity category were associated with multiple impairments in sleep quality, but only high BMI predicted sleep quality at T2. Thus, night-eating and measures of body fatness predicted sleep quality components at T1 and T2 even after co-existing behaviour and emotional states were taken into account.</p>