Psoriasis is a chronic autoimmune disease of undefined etiology that involves dysregulated interplay between immune cells and keratinocytes. Acarbose was found to decrease inflammatory parameters in diabetic patients in addition to its anti-diabetic effects. Here, we report that imiquimod (IMQ)-induced epidermal hyperplasia and psoriasis like-inflammation were significantly inhibited by acarbose treatment. Real-time PCR showed that mRNA levels of the cytokines TNF-α, IL-6, IL-1β IL-17A, and IL-22 in skin were also decreased significantly by acarbose. In addition, we found that acarbose reduced infiltration of CD3⁺ T cells and GR-1⁺ neutrophils in lesional skin and also reduced the percentage of IL-17-producing CD4⁺ T cells (Th17) and IL-17- and IL-22-producing γδ T cells in the spleen. In contrast, acarbose increased the frequency of IL-10-producing CD4⁺ regulator Tr1 T cells in the spleen and small intestine. These results indicate that oral administration of acarbose can attenuate the severity of imiquimod-induced psoriasis with local and systemic anti-inflammatory and immune modulation effects, thus suggesting that acarbose is an effective therapeutic strategy for psoriasis regulation.