Aims: To investigate the prevalence of and contributors to poor sleep quality in patients with mild cognitive impairment (MCI). Methods: Data were collected for 158 patients meeting the criteria for MCI. Measures included the Pittsburgh Sleep Quality Index, Geriatric Depression Scale, and Mini-Mental State Examination. Demographic, lifestyle, medication, and substance use data were also collected. Results: A total of 63% of patients with MCI demonstrated sleep disturbance, a significantly higher rate than that of the controls (44%; chi-square = 8.77; P = .003). Depressive symptoms, cognition, antidepressant usage, alcohol consumption, age, and education were identified as significant predictors of self-reported sleep quality in patients with MCI (R2 = .327, F6,145 = 11.729, P < .0001). Conclusions: Sleep disturbance occurs in around two-thirds of patients with MCI. Interventions addressing depression, cognition, and substance and medication use may improve sleep quality in MCI.