We herein report a case of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A 24-year-old woman developed unilateral optic neuritis 3 weeks after contracting coronavirus disease 2019 (COVID-19), followed by intracranial demyelinating lesions and myelitis. Since serum anti-MOG antibody was positive, we diagnosed MOG antibody-associated disease. Immunotherapy with steroids resulted in the rapid improvement of neurological symptoms. This is a suggestive case, as there are no reports of MOG antibody-associated disease with multiple neurological lesions occurring after COVID-19. The response to immunotherapy was favorable. This case suggests that it is important to measure anti-MOG antibodies in patients who develop inflammatory neurological disease after COVID-19.