Objective: Limited information is available regarding the associations between upper extremity function, activities of daily living (ADLs), and functional capacity in patients with heart failure with reduced ejection fraction (HFrEF). This study aimed to investigate the associations between upper extremity function, ADLs, and functional capacity in patients with HFrEF. Methods: This cross-sectional study included 31 patients with HFrEF. Demographic, anthropometric, and clinical data were recorded. Upper extremity function and ADLs were evaluated using the 6-Minute Pegboard and Ring Test (6PBRT) and the Glittre Activities of Daily Living Test (TGlittre), respectively. The 6-Minute Walk Test (6MWT) was administered to measure functional capacity. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), peripheral oxygen saturation (SpO2), dyspnea, and fatigue were assessed at the beginning and end of each test. Results: The 6PBRT was significantly correlated with TGlittre (rho = -0.718, P < 0.001) and 6-minute walk distance (6MWD) (r = 0.546, P = 0.001). A significant correlation was also found between TGlittre and 6MWD (rho = -0.810, P < 0.001). Changes in HR, SBP, and dyspnea were significantly different across the 6PBRT, TGlittre, and 6MWT (P < 0.05). Conclusion: This study indicates that upper extremity function is associated with ADLs and functional capacity in patients with HFrEF. The 6PBRT requires lower cardiopulmonary demand than TGlittre and 6MWT in this patient population.