Granulomatous meningoencephalomyelitis (GME) is a nonsuppurative inflammatory disease of unknown origin that affects the central nervous system of dogs. GME is characterized histologically by large perivascular cuffs of mononuclear cells in the parenchyma and meninges of the brain and spinal cord. If left untreated, it is usually fatal. Immunosuppressive doses of glucocorticosteroids have been the mainstay of treatment for GME; however, new and more effective therapies have recently been proposed. This article reviews the pathology, origin, clinical signs, therapeutic response, and outcome of GME in dogs.