The commensal microbiota contributes to the maintenance of immune homeostasis in the human body. Autoimmunity can be aggravated or alleviated by the microbiota, which affects both innate and adaptive immune cells. Many studies have demon-strated the role of gut dysbiosis, the alteration of the gut microbiome, in the development and progression of numerous auto-immune diseases. Systemic sclerosis (SSc) is an autoimmune disease of the connective tissue and is characterized by skin and lung fibrosis, as well as injuries in small arteries. Recent studies have shown variable degrees of dysbiosis in SSc patients and the effect of probiotics on these patients, providing evidence for the potential link between microbiota and SSc. However, fur-ther research is needed to elucidate the key microorganisms and the mechanisms through which they affect the pathoimmuno-logical process of SSc. This review summarizes the current knowledge regarding the association between microbiota and SSc, and discusses the changing perspectives and potential therapy strategies based on the microbiota and its products. (J Rheum Dis 2019;26:235-247)