Few studies have focused on factors associated with sedentary behaviour among older Asian adults. This study aimed to identify factors independently associated with prolonged sedentary times in Korean older adults. We included 8273 community-dwelling older adults aged ≥65 years who participated in the Korean National Health and Nutrition Examination Survey. Self-reported sedentary times were assessed via the Global Physical Activity Questionnaire, and sedentary times of ≥420 min/day were considered 'long'. Complex-sample multivariable-adjusted logistic regression analyses were conducted to investigate the factors associated with long sedentary times. Among the participants, 4610 (55.72%) had long sedentary times that were associated with advanced age (odds ratio OR, 2.49; 95% confidence interval CI, 2.05-3.01), female sex (OR, 1.32; 95% CI, 1.11-1.57), unemployment (OR, 1.23; 95% CI, 1.09-1.38), living alone (OR, 1.24; 95% CI, 1.08-1.43), urban residence (OR, 1.35; 95% CI, 1.14-1.61), and insufficient aerobic exercise (OR, 1.80; 95% CI, 1.60-2.02). Among health factors, obesity (OR, 1.27; 95% CI, 1.12-1.45), diabetes (OR, 1.17; 95% CI, 1.04-1.32), cardiovascular diseases (OR, 1.30; 95% CI, 1.11-1.52), and arthritis (OR, 1.26; 95% CI, 1.11-1.43) had positive associations with long sedentary times. A tailored approach that considered various sociodemographic, behavioural, and health factors is needed to reduce sedentary behaviour in this population.