The association between smoke habit and autoimmunity has been hypothesized a long time ago. Smoke has been found to play a pathogenic role in certain autoimmune disease as it may trigger the development of autoantibodies and act on pathogenic mechanism possibly related with an imbalance of the immune system. Indeed, both epidemiological studies and animal models have showed the potential deleterious effect caused by smoke. For instance, smoke, by provoking oxidative stress, may contribute to lupus disease by dysregulating DNA demethylation, upregulating immune genes, thereby leading to autoreactivity. Moreover, it can alter the lung microenvironment, facilitating infections, which, in turn, may trigger the development of an autoimmune condition. This, in turn, may result in a dysregulation of immune system leading to autoimmune phenomena. Not only cigarette smoke but also air pollution has been reported as being responsible for the development of autoimmunity. Large epidemiological studies are needed to further explore the accountability of smoking effect in the pathogenesis of autoimmune diseases.