Gait disorders are common in people with Parkinson's disease (PD) yet their associations with activity limitations remain poorly understood. The objective of this review is to investigate the relationships between gait impairments and activity limitations in people with idiopathic PD. Six electronic databases (MEDLINE ISI, CINAHL, Web of Science ISI, EMBASE, PsycINFO and Scopus) were systematically searched using relevant terms to source for English-language studies published between 1900 and January 2011. Only studies that reported associations between impairments and activity limitations were considered for the review. The methodological quality of eligible studies was evaluated using a customized checklist by two independent reviewers. Data on participant characteristics, disease severity and associations between variables were extracted using a standardized data extraction form. Correlation coefficients were transformed to standardized scores and pooled using the fixed or random effects models. 16 of the 1735 studies screened were included, comprising 1882 participants. Large effect sizes were found between postural instability measured by the Berg Balance scale and activity limitation measured by the Unified Parkinson's Disease Rating Scale Activities of Daily Living (UPDRS ADL) section (-0.81; 95% CI, -0.99 to -0.63; p < 0.001). Gait hypokinesia measured by gait speed was significantly correlated with UPDRS ADL (-0.41; 95% CI, -0.56 to -0.26; p < 0.001). Gait freezing measured by the Freezing of Gait Questionnaire was associated with reduction in ADL (0.45; 95% CI, 0.36 to 0.54; p < 0.001). Knowledge of gait disturbances and their associations with disability may help to guide clinicians in assessing patients to optimize functional outcomes.