Copyright © 2017 by The American Association of Immunologists, Inc. The mechanisms leading to autoimmune and inflammatory diseases in the CNS have not been elucidated. The environmental triggers of the aberrant presence of CD4+T cells in the CNS are not known. In this article, we report that abnormal β-catenin expression in T cells drives a fatal neuroinflammatory disease in mice that is characterized by CNS infiltration of T cells, glial activation, and progressive loss of motor function. We show that enhanced β-catenin expression in T cells leads to aberrant and Th1-biased T cell activation, enhanced expression of integrin α4β1, and infiltration of activated T cells into the spinal cord, without affecting regulatory T cell function. Importantly, expression of β-catenin in mature naive T cells was sufficient to drive integrin α4β1 expression and CNS migration, whereas pharmacologic inhibition of integrin α4β1 reduced the abnormal T cell presence in the CNS of β-catenin-expressing mice. Together, these results implicate deregulation of the Wnt/β-catenin pathway in CNS inflammation and suggest novel therapeutic strategies for neuroinflammatory disorders.