Interleukin-22 (IL-22) is a member of the IL-10 superfamily of cytokines. These cytokines are pleiotropic and affect a wide range of immune functions. IL-22 is produced by Dendritic, T, and Innate Lymphoid cells and can be found in a wide range of tissues. IL-22 promotes the function of the innate immune system and tissue repair. Serum levels correlate with the severity of psoriasis, and therapeutics targeting IL-22 may have promise as a potential therapeutic target for treating psoriasis. Emerging evidence suggests that IL-22 can play a role in other autoimmune disorders such as IBD, RA, and MS, perhaps due to its role in inflammatory responses, which are regulated by the often co-expressed cytokine IL-17A.