Abstract: This study examines the relationship between sleep duration and cognitive performance in a sample of 200 participants aged 18-60. Participants completed a battery of cognitive tasks measuring attention, memory, and executive function after selfreporting their average nightly sleep duration over the past month. Sleep duration was categorized into three groups: short (≤ 6 hours), normal (7-8 hours), and long (≥ 9 hours). Results from the analysis revealed a significant main effect of sleep duration on cognitive performance (F(2,197) = 9.73, p < 0.001). Post-hoc comparisons using Tukey’s HSD test indicated that participants in the short sleep group performed significantly worse on attention (p = 0.003), memory (p = 0.012), and executive function tasks (p = 0.009) compared to those in the normal sleep group. Additionally, participants in the long sleep group exhibited significantly poorer memory performance (p = 0.026) compared to the normal sleep group. However, there were no significant differences in attention or executive function between the long and normal sleep groups. Furthermore, age was found to moderate the relationship between sleep duration and cognitive performance (F(4,197) = 3.28, p = 0.012). Specifically, younger participants (< 30 years) in the short sleep group demonstrated the greatest cognitive deficits compared to their counterparts in the normal and long sleep groups. These findings underscore the importance of adequate sleep duration for maintaining optimal cognitive function across different age groups. Practical implications for promoting healthy sleep habits and cognitive well-being are discussed.