In this report, we describe a novel, potent and highly selective small molecule inhibitor for RORγ/RORγt, that markedly inhibits Th17-type cytokine production in multiple assay systems, including (i) in vitro reporter assays, (ii) the in vivo imiquimod mouse model, and (iii) human tissue-based assays, including human peripheral T cells, Th17-skewed ex vivo human skin and psoriatic biopsy cultures from psoriasis patients. Here, RORC is linked to psoriasis.