Introduction: The incorporation of digital devices into academic activities during COVID-19 pandemic increased children’s screen time. Although previous studies suggest an association between early screen exposure and cognitive performance, local evidence remains limited. Objectives: To determine the association between digital device usage and cognitive development among primary school children in grades three and four in the Sri Jayewardenepura Educational Zone. Methods: A cross-sectional study was conducted in cluster-selected schools. A selfadministered questionnaire collected socio-demographics and digital device usage data. Cognitive development was assessed using a culturally adapted tool with experts face and content validity . Results: A total of 197 grades 3 and 4 students participated. Mean digital device usage was 1.18 hours (SD = 0.67) on weekdays and 1.46 hours (SD = 0.95) on weekends. The mean cognitive score was 55.80 (SD = 10.52). No significant association was found between device usage and cognitive scores on weekdays (? ² = 0.293, p = 0.58) or weekends (? ²= 0.543, p = 0.46). Significant associations were observed between weekday usage and primary caretaker (? ² = 4.688, p = 0.030), weekend usage and screen-free playtime (? ² =11.875, p = 0.001), and household income with weekend usage (? ²= 5.478, p = 0.019) suggesting that caregiver presence, screen-free playtime, and income influence usage patterns. Conclusion: Average device use remained within the recommended limit of