<![CDATA[Introduction: Sedentary behavior has emerged as a major public health concern among adolescents due to rapid digital transition and lifestyle changes. Prolonged sitting and excessive recreational screen time significantly disrupt physical homeostasis and sleep patterns. Objective: This study aimed to examine the relationship between sedentary behavior and sleep quality among students at SMP Negeri 1 Sindang Jaya. Methods: A quantitative study with a cross-sectional design was conducted in May–June 2026. The population comprised 249 eighth-grade students across seven classes. A sample of 154 students was selected using proportional stratified sampling and purposive sampling based on predefined eligibility criteria. Sedentary behavior was measured using the Indonesian version of the Adolescent Sedentary Activity Questionnaire (ASAQ), while sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI). Univariate frequency distributions and bivariate Spearman rank correlation analysis were performed with a significance threshold of alpha = 0.05. Results: Most respondents were female (51.9%) and aged 14–15 years (95.5%). A total of 135 respondents (87.7%) exhibited high sedentary behavior (>5 hours/day), and 124 respondents (80.5%) experienced poor sleep quality (PSQI score >5). The bivariate analysis revealed a statistically significant positive relationship between sedentary behavior and sleep quality (r = 0.555, p = 0.000). Conclusion: Higher sedentary behavior is moderately associated with poorer sleep quality. School-based physical activity interventions and parental digital monitoring are recommended to mitigate sleep disturbances among schooling adolescents.]]>
