Myasthenia gravis is an autoimmune disease in which autoantibodies affect the neuromuscular junction, leading to muscle loss. Steroids are the primary immunosuppressive treatment for this condition. Since steroids affect the immune system and are effective in most subtypes of myasthenia gravis, they are often used for long-term maintenance treatment. This increases the probability of steroidassociated side effects such as decreases in bone mineral density and increased risk of fractures. The authors successfully treated an 18-year-old female who had been using steroids for a long time after being diagnosed with myasthenia gravis using teriparatide for osteoporotic multi-segment thoracolumbar compression fractures that occurred without trauma with satisfactory outcomes. Since there have been no reports of osteoporotic multi-segmental thoracolumbar compression fractures and treatment in juvenile myasthenia gravis patients caused by long-term steroid use, we report this case along with a review of the literature.