Introduction Systemic sclerosis (SSc) is a complex disease linked to immune system activation, vascular damage, associated with increased synthesis, and deposition of extracellular matrix, which contain excessive amounts of structurally normal collagen. Interleukin 23 (IL-23) might play a role in disease development and severity. This study aimed to assess the relationship between serum level of IL-23 and interstitial lung disease in SSc. Patients and methods Thirty patients with SSc together with 30 age-matched and sex-matched healthy volunteers were recruited in this study. Serum IL-23 levels were measured by enzyme-linked immunosorbent assay. Functionally, lung involvement was assessed by pulmonary function tests and radiologically by chest radiography and high-resolution computed tomography of the lungs. Results Mean serum IL-23 level was significantly highly elevated in SSc patients compared with healthy controls (P