This systematic review critically evaluates the literature to identify the demographic and clinical factors that predict the health-related quality of life (HRQOL) of people with Parkinson's disease (PD). Understanding how these factors relate to HRQOL in people with PD may assist clinicians minimise the functional and social impact of the disease by optimising their assessment and clinical decision making processes. A tailored search strategy in six databases identified 29 full-text reports that fulfilled the pre-defined inclusion and exclusion criteria. The quality of included studies was assessed by two independent reviewers using a customized assessment form. A best-evidence synthesis was used to summarise the demographic and clinical factors that were examined in relation to HRQOL. Depression was the most frequently identified determinant of HRQOL in people with idiopathic PD. Disease severity and disease disability were also found to be predictive of poor HRQOL outcomes in many studies. The motor symptoms that contributed most often to overall life quality were gait impairments and complications arising from medication therapy. To minimise the impact of PD on HRQOL, it may be necessary to consider the extent to which demographic factors and motor and non-motor symptoms contribute to life quality.