Aims Fatigue, a distressing symptom in patients with heart failure (HF), is associated with progress and health outcomes. Fatigue has been identified as having multi-dimensions, but few study used multidimensional fatigue scale. Many factors related to HF, including physical, psychological, and situational factors, may impact fatigue. However, there is limited knowledge about how these HF-related factors are associated with multidimensional fatigue in outpatients with HF in Japan. The aim of this study was to identify HF-related factors (physical; clinical characteristics, New York Heart Association functional class (NYHA) and physical function, psychological; depressive symptoms and anxiety, situational; health literacy and perceived control) associated with the five dimensions of fatigue in outpatients with HF. Methods and Results Outpatients with HF (N = 165, mean age = 69.5 years, 78.8% male) completed the survey and physical assessment of gait speed. Fatigue was assessed using 5 dimensions of the Multidimensional Fatigue Inventory-20. Multiple linear regression analysis was conducted for each dimension of fatigue. General fatigue was predicted by age, NYHA, and perceived control. Physical fatigue was predicted by NYHA, depressive symptoms, and perceived control. Reduced activity was predicted by NYHA, gait speed, depressive symptoms, communicative health literacy, and critical health literacy. Reduced motivation was predicted by depressive symptom and perceived control. Mental fatigue was predicted by depressive symptoms. Conclusions Different factors were significantly associated with each fatigue dimension. Further research is needed to alleviate fatigue in patients with HF.