The etiology of sleep problems in Parkinson disease (PD) is not well understood, as they may arise from the pathology of the disease or from other disease-related factors such as motor dysfunction, dopaminergic medication, and mood disturbances. The aim of this study was to investigate factors associated with sleep, including disease-related variables such as motor symptom severity, dose of medication, and mood and disease subtypes. Thirty-five nondemented patients with PD were included. Sleep was measured using 24-hour wrist actigraphy over a 7-day period, during which time participants kept a sleep diary. Subjective sleep and arousal questionnaires included the PD Sleep Scale and Epworth Sleepiness Scale. Motor symptom severity and dopaminergic medication were significantly related to measures of sleep quality. Sex differences in sleep quality were found, with men having worse sleep quality and more excessive daytime sleepiness than women. We also found that actigraphy may serve as a useful tool for identifying individuals with possible rapid eye movement behavior disorder, a sleep disorder that has important implications in early detection of PD.