Purpose: Upper extremities play an important role in performing of many activities of daily living. Physical and pathological changes limit upper extremity functions in older adults with chronic obstructive pulmonary disease (COPD). Although the 6-minute pegboard and ring test (6PBRT) is a reliable and commonly used method for the assessment of unsupported upper-extremity exercise capacity in patients with COPD, there is lack of evidence about the possible determinants of the 6PBRT score. The study aimed to investigate the possible determinants of the 6PBRT in older adults with COPD. Methods: Fifty-two older adults (age ≥ 65 years) with stable COPD and 23 age-matched healthy older adults participated in this study. Demographic characteristics, unsupported upper-extremity exercise capacity, pulmonary function, functional exercise capacity, disease related symptoms, peripheral and respiratory muscle strength were evaluated. Stepwise multiple linear regression analysis was used to investigate the possible determinants of the 6PBRT score. Results: The 6PBRT score was significantly higher in healthy participants compared with those with COPD (p = 0.024). In participants with COPD, shoulder flexor muscle strength, age and functional exercise capacity were significant and independent predictors of the unsupported upper-extremity exercise capacity with explaining 55.4% of the variance. Conclusions: This study suggests that shoulder flexor muscle strength, age and functional exercise capacity are independent determinants of the unsupported upper-extremity exercise capacity assessed by the 6PBRT in older adults with COPD.