Sleep disturbances are prevalent in Parkinson disease (PD), encompassing a spectrum from parasomnias like REM sleep behavior disorder to symptoms of sleep-wake cycle dysregulation, such as insomnia and daytime sleepiness. This research investigates sleep quality in PD patients compared with a matched healthy control group and explores the relationships between PD clinical characteristics and sleep parameters. Additionally, the study assesses the reliability of the Pittsburgh Sleep Quality Index (PSQI) for PD patients by examining internal consistency. The study comprises 52 participants, 27 in the PD group and 25 in the healthy control group, matched for sex and age. Sleep quality revealed that PD patients experienced significantly poorer sleep quality than the control group (  = 0.009). Weak correlations were found between PSQI scores and the modified Hoehn and Yahr scale (  = 0.062), with no correlation observed with the daily equivalent dose of levodopa (L-DOPA). The prevalence of poor sleep quality (PSQI score > 5) was 85.1% for PD patients and 68% for the control group. The internal consistency analysis of the PSQI yielded a Cronbach's α of 0.588 for the PD group. While the PSQI demonstrates utility in detecting general sleep abnormalities and gauging patient perceptions of sleep quality in PD, its limitation as a global score is emphasized. The index prioritizes sleep habits and may not fully capture important sleep disorders in this population. These findings underscore the complex relationship between PD and sleep quality, suggesting the need for a comprehensive approach to assess and address sleep disturbances in PD patients.