IntroductionMyasthenia gravis is a neuromuscular autoimmune condition characterized by the presence of antibodies against acetylcholine receptors. It may present as a generalized disorder or remain limited to specific muscle groups. Myasthenia gravis can occur independently or alongside other autoimmune conditions, including Hashimoto s thyroiditis and Graves disease. Although the co-occurrence of these disorders is recognized, it is an extremely rare clinical phenomenon.Case presentationA 20-year-old woman of Muganda ethnicity, with a 2-year history of Graves disease confirmed by thyroid scintigraphy, developed a myasthenic syndrome leading to acute respiratory failure. Her condition improved with the administration of Prostigmine. Further investigations, including electrophysiological studies and immunological tests, confirmed a diagnosis of myasthenia gravis. The patient demonstrated a positive response to medical therapy.ConclusionThis case highlights the importance of recognizing the rare association between myasthenia gravis and Graves disease. Accurate diagnosis and effective treatment require a coordinated, multidisciplinary approach, particularly given the challenges posed by overlapping symptoms and the exacerbating effects of hyperthyroidism on myasthenia gravis.