OBJECTIVE We aim to identify prognostic factors for visual outcomes following a first episode of neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON) in affected eyes. METHODS This was a single-center, retrospective study. The study included 50 individuals who were diagnosed with NMOSD-ON (63 affected eyes) in a tertiary institution over a 12-year period. Data regarding any second, or higher, episodes of NMOSD-ON in each eye were not taken into consideration. Medical records of included individuals were reviewed. Demographic data, clinical and magnetic resonance imaging characteristics, and treatment outcomes were collected. Main outcome measures of the study were prognostic factors for good visual outcome (best-corrected visual acuity (BCVA) ≥ 20/200) following an initial episode of NMOSD-ON in affected eyes. RESULTS Sixty-three affected eyes of 50 individuals (3 men and 47 women) were included. BCVA at nadir that was better than counting fingers (CF) (odds ratio 10.43, 95% confidence interval 1.04, 104.45, p = 0.046) and time from NMOSD-ON onset to intravenous methylprednisolone (IVMP), less than 21 days (odds ratio 10.73, 95% confidence interval 1.91, 60.01, p = 0.007), were significantly associated with good visual outcomes. CONCLUSIONS BCVA at nadir that was better than CF and treatment with IVMP within 21 days of symptom onset were important prognostic factors of good visual outcomes following a first episode of NMOSD-ON in affected eyes.