Vitamin D status has been linked to immune system and autoimmune disorders; in fact, low levels of vitamin D are common in many autoimmune disorders. The aims of our study were to assess the prevalence of vitamin D insufficiency and the possible correlation with clinical parameters in systemic sclerosis (SSc). We recruited 40 patients (38 female and two male) with scleroderma and 40 healthy controls matched for age and gender. Demographic and clinical parameters were recorded and the 25-hydroxivitamin D3 serum levels were measured. Serum 25-hydroxivitamin D3 levels were significantly lower in patients with systemic sclerosis than in the control group. The prevalence of 25-hydroxivitamin D3 insufficiency was 50% in the patients and 22.5% in the control group. A statistically significant association was observed between the insufficiency of 25-hydroxivitamin D3 and skin involvement (p = 0.02) and echocardiography systolic pulmonary artery pressure >35 mmHg (p = 0.02). Our data show that the systemic sclerosis group has significantly lower serum 25-hydroxivitamin D3 concentrations compared to the control group; skin involvement and pulmonary hypertension are associated with vitamin D3 insufficiency.