BackgroundPhysical inactivity and sedentary behaviour have become major public health concerns among children and adolescents due to their potential associations with physical, psychological, and educational outcomes. This study aimed to examine the associations between sedentary behaviour and self-esteem, emotional regulation, academic motivation, and sleep disorders among primary school students.MethodsA cross-sectional study was conducted with 185 students aged 9-12 years from two primary schools in Jaén, Spain. Sedentary behaviour was assessed using the Sedentary Behavior Questionnaire, while self-esteem, emotional regulation, academic motivation, and sleep disorders were evaluated using validated instruments. Multiple linear regression analyses were performed adjusting for age, sex, and body mass index.ResultsHigher levels of sedentary behaviour were associated with lower emotional regulation, greater emotional lability/negativity, lower intrinsic motivation, and a higher prevalence of sleep disorders. Although sedentary behaviour was negatively correlated with self-esteem, this association was no longer statistically significant after adjustment for potential confounders. The strongest association was observed for sleep disorders. No significant sex differences were found in sedentary behaviour or the outcomes assessed.ConclusionsHigher sedentary behaviour was associated with less favorable emotional, motivational, and sleep-related outcomes among primary school students, with the strongest association observed for sleep disorders. Given the cross-sectional design, these findings do not establish causal relationships. Longitudinal and intervention studies are needed to clarify the direction of these associations and determine whether reducing sedentary behaviour may contribute to improved well-being in school-aged children.