Our ability to successfully treat patients with moderate to severe psoriasis has improved significantly over the last several years with the development of more targeted therapies. IL-17A, a member of the IL-17 family of interleukins, is involved in regulating the innate and adaptive immune systems and has been identified as a key cytokine involved in the pathogenesis of psoriasis and psoriatic arthritis. In this review, we summarize our understanding of IL-17 and its role in psoriasis and psoriatic arthritis, as well as key findings from clinical trials using anti-IL-17 medications for the treatment of the aforementioned diseases. Secukinumab, ixekizumab, and brodalumab are three anti-IL-17 medications used for treating psoriasis, of which only secukinumab is FDA approved; ixekizumab and brodalumab remain under clinical development. Results from clinical trials show that these three medications are highly effective in treating psoriasis and appear to be as safe as other biologic treatments that are FDA approved.