Introduction Sleep problems, including obstructive sleep apnea (OSA), profoundly affect quality of life in patients with systemic sclerosis (SSc). This study aimed to determine the prevalence of OSA in patients with SSc and the factors affecting OSA. Methods Consecutive patients with SSc lung involvement who were referred to the "Outpatient Service for Interstitial Lung Disease" in our university hospital between 2015 and 2017 were included in the study. All patients completed the Epworth Sleepiness Scale (ESS) and underwent examination including body mass index (BMI), measurement of waist circumference, upper respiratory tract examination, and polysomnography (PSG). Spirometry, carbon monoxide diffusion test (DLCO), and 6-min walking distance were also performed. Results Of 38 patients, mean age 51.3 +/- 11.6 years, 35 were women (92%). Mean apnea-hypopnea index (AHI) was 11 +/- 15 (median 5.5) and prevalence of OSA was 58%. Mild OSA was found in 13 (34%) of patients, moderate OSA in 6 (16%), and severe OSA in 3 (8%). Significant relationships were found between age (p = 0.02), waist circumference (p = 0.01), presence of witnessed apneas (p = 0.005), and presence of OSA. Conclusions Compared with the general population, the prevalence of OSA is increased in women with SSc. Patients with older age, those with increased waist circumference, and those reporting witnessed apneas should be studied for OSA.