Abstract Multiple sclerosis is a chronic autoimmune disease driven by pathogenic Th17 cells. In this study, we dissected the role of miR-22 in pathogenic Th17 cells by autoantigen-specific disease models. We first showed that miR-22 was upregulated in peripheral lymphoid organs and spinal cords of mice developed autoimmune encephalomyelitis. Although miR-22 was upregulated in multiple Th cell subsets, it was dispensable for Th cell differentiation in vitro. Whereas miR-22−/− mice exhibited milder symptoms of disease in an active experimental autoimmune encephalomyelitis model, adoptive transfer of miR-22−/− 2D2 Th17 cells into naive recipient mice promoted higher disease incidence and severity compared with mice transferred with control 2D2 Th17 cells. Global transcriptional analysis of miR-22–deficient pathogenic Th17 cells revealed upregulated genes in phosphatase and tensin homologue (PTEN)–mediated pathways, and Pten was further identified as one of its potential targets. Therefore, we identified that Th17 cell–intrinsic miR-22 could protect mice from autoimmunity by targeting PTEN-regulated pathways.