Optic neuritis (ON) in a patient of systemic lupus erythematosus (SLE) overlapping with neuromyelitis optica spectrum disorder (MNOSD) was a rare occasion. We presented a 24-year-old female with the complaint of progressive visual loss associated with eye pain in the right eye for 5 days. She had past history of SLE with well control. Her vision decreased to hand motion. Right optic neuritis was impressed after ocular examination. Pulse steroid for 3 days was given and followed by slow tapering oral steroid. Further evaluation revealed positivity of AQP4-IgG and immunosuppressive therapy was augmented. Her vision improved to 20/25 after treatment. The presence of ON in a patient of SLE should warrant the testing for AQP4-IgG. Although there are no specific recommendations for the treatment of SLE/MNOSD overlapping cases, early pulse steroid was necessary. Long term immunosuppression should be considered as an effective way to attack prevention.