Approximately one-third of children with an acquired demyelinating syndrome (ADS) will be diagnosed with multiple sclerosis (MS), either at onset according to the 2010 McDonald criteria, or on the basis of clinical or MRI evidence of relapsing disease, in the majority of patients within 2–4 years. ADS in adolescents, female patients, and patients with polyfocal deficits is associated with the highest likelihood of MS, while children with acute disseminated encephalomyelitis, those with documented preceding infection, and ADS presentation in young children more commonly portends a monophasic outcome. While pediatric MS associates with similar genetic risk alleles as have been documented in adult-onset MS, such associations are not diagnostically valuable at the individual level. The presence of antibodies directed against aquaporin-4 strongly supports a diagnosis of neuromyelitis optica, and should be assayed in children manifesting with severe optic neuritis, longitudinally extensive myelitis, or brainstem/hypothalamic syndromes. Further research will determine whether other antibody signatures are indicative of relapsing demyelination distinct from MS.