Neuromyelitis optica spectrum disorder is an inflammatory syndrome that is associated with many autoimmune conditions. We present the case of a patient who had longitudinally extensive transverse myelitis and antibodies to aquaporin 4 IgG (AQP4-IgG). Based on presence of lymphopenia, further workup revealed strong ANA positivity, anti-Sm antibodies, and low serum complements suggesting presence of systemic lupus erythematosus. The patient promptly responded to intravenous pulse methylprednisolone and five sessions of plasma exchange. At 1 year, she is on maintenance treatment with low dose prednisolone, azathioprine, and hydroxychloroquine, she has had no relapse and no other clinical features of lupus. This case is an illustration that neuromyelitis optica spectrum disorder can be the first manifestation of systemic lupus erythematosus.