Adhering to a gluten-free diet (GFD) is becoming a popular health trend. In this chapter we summarize the current clinical evidence on a potential role for gluten in multiple sclerosis (MS), psoriasis, autoimmune thyroid diseases (ATD), and type 1 diabetes (T1D). Patients with celiac disease have increased risk of ATD, T1D, psoriasis and vice versa, however this is not the case for MS. One clinical trial has found protective effects of a GFD among patients with MS. A few studies suggest that a subgroup of patients with psoriasis presenting gliadin antibodies can benefit from a GFD. No studies have investigated the effects of a GFD in nonceliac patients with ATD, however, some publications suggest that thyroid-related antibodies may respond to a GFD in patients with confirmed CD or tissue transglutaminase antibodies. Lastly, results on the effects of a GFD among patients with T1D are inconsistent, however, it seems likely that a GFD may contribute to normalizing metabolic control possibly by preserving the function of the remaining beta-cells. Altogether, the above results have to be replicated in properly controlled intervention trials of adequate power before we can recommend a GFD to subgroups of patients with autoimmune disorders.