Tapinarof is a non-steroidal, small molecule aryl hydrocarbon receptor (AhR) agonist that has demonstrated clinical efficacy and safety in patients with plaque psoriasis. In this study, we investigated the effects of tapinarof on interleukin (IL)-23-induced psoriasis-like dermatitis, which is a direct reflection of IL-23/type 17 helper T (Th17) axis activation considered pivotal in the pathogenesis of psoriasis, or normal skin in mice to elucidate its pharmacological properties. In mice with dermatitis, topical administration of tapinarof induced AhR activation, promoted the expression of an antioxidant molecule, and suppressed Th17 cytokine production in the skin, resulting in the reduction of skin swelling and histopathological changes. In normal mice, tapinarof did not induce the skin thinning observed with dexamethasone. These findings suggest that tapinarof represents a new topical treatment option for psoriasis carrying a lower risk of skin atrophy.