To summarise the evidence of the efficacy and safety of current long-term immunotherapies in patients with myelin oligodendrocyte glycoprotein antibody disease (MOG-AD).We performed a sensitive literature search in MEDLINE and EMBASE for selected studies or case series discussing the long-term treatments and outcomes in adult patients with MOG-AD and conducted a qualitative analysis of each therapy.A total of 33 articles, including 712 patients with MOG-AD, matched our inclusion criteria, and seven kinds of drugs were analysed accordingly. Efficacy was mainly reflected by the change in the annual relapse rate before and after treatment. First, maintenance steroids, azathioprine, mycophenolate mofetil, and rituximab were demonstrated to be effective in multiple studies. However, relapses could still happen after therapy especially under specific circumstances. Second, regular intravenous immunoglobulin G (IVIG) and tocilizumab might be effective. IVIG reduced annual relapse rate and expanded disability status scale in five adult patients, and tocilizumab succeeded in preventing relapse in four refractory patients, though with scant evidence. Finally, multiple sclerosis-disease-modifying therapy seemed ineffective for patients with MOG-AD. As for safety, six patients experienced severe neutropenia during rituximab therapy. No other serious adverse events were reported for these treatments.Several preventive immunotherapies have been demonstrated to be effective and safe for adult patients with MOG-AD; however, large controlled studies for subgroups with specific manifestations are still needed in the future.