The COVID-19 virus has been responsible for the development of several systemic diseases. Recently, the COVID-19 vaccine has also been incriminated in the development of autoimmune diseases. Currently, researchers have focused on the relationship between the COVID-19 vaccine and the activation of autoimmune phenomenon. We report a case of Graves' disease (GD) whose symptoms appeared 3 days after vaccination against COVID-19. A forty-three-year-old female, without pathological history, presented with diarrhea and palpitation. She received her first SARS-CoV-2 Vaccine dose (Pfizer-BioNTech), in August 2021. Three days after the vaccine, she felt palpitations, sleep disorders, muscle weakness, and heat intolerance. On examination, her pulse was 119 beats per minute, she weighed 63 kg, and she had lost 4 kg in only two months. GD was suspected. Thyroid hormone testing showed low thyroid-stimulating hormone, and an elevated serum free thyroxine hormone T4 level. Serology tests were positive for TSH receptor autoantibodies (TRAB). A GD induced by adjuvants of SARS-CoV-2 vaccine has been retained as a final diagnosis. Several autoimmune diseases have been attributed to adjuvant-induced autoimmune/inflammatory syndrome, including systemic sclerosis, systemic lupus erythematosus and rheumatoid arthritis, and recently few cases of GD have been explained by this phenomenon.