OBJECTIVE: Fatigue is a common and debilitating non-motor symptom of Parkinson's disease (PD), arising from a complex interplaying underlying factors. While mental health and sleep are well-established evidence regarding motor symptoms, balance, gait, and cognition remain inconsistent. By explicitly examining multiple symptom domains within the same cohort, we aimed to identify which factors are most strongly associated with fatigue in PD. METHODS: This cross-sectional study included 64 individuals with PD. Fatigue was measured using the Functional Assessment of Chronic Illness Therapy-Fatigue scale (FACIT-F). The association between fatigue and a broad set of factors within and across four symptom categories - Disease-specific, Balance and gait, Cognition, and Neuropsychiatric symptoms - was analysed using linear regression analysis. RESULTS: The mean age was 69.3 years, and the disease duration was 7.8 years. Median motor symptom (UPDRS III) and fatigue (FACIT-F) were 14 and 35.5, respectively. Regression analyses revealed significant associations with fatigue within all four categories. In the final model, self-perceived walking difficulties were the strongest independent associated factor to fatigue, followed by depression, functional balance, dynamic balance and comfortable gait speed. Together, these factors explained 70% of the variance in fatigue. CONCLUSION: Walking difficulties and depression, but not cognition, were key factors associated with fatigue, underscoring the interplay of motor and non-motor factors of psychological health character. These findings highlight the need for comprehensive assessments and targeted interventions to effectively manage fatigue in PD.