Background: The autoimmune/inflammatory syndrome induced by adjuvants (ASIA) comprises four entities, including the postvaccination phenomenon, which appears after being exposed to adjuvants in vaccines that increase the immune response. There is limited information about autoimmune endocrine diseases and ASIA after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Patient's Findings: Two female health care workers received a SARS-CoV-2 vaccine, and three days later developed clinical manifestations of thyroid hyperactivity, with increased thyroid hormone levels on thyroid function tests, suppressed thyroid-stimulating hormone, and elevated antithyroid antibodies. Summary: Vaccines have been shown to trigger an immune response that leads to a broad spectrum of autoimmune diseases, including autoimmune thyroid disease. Our patients met the diagnostic criteria for ASIA; they were exposed to an adjuvant (vaccine), and they developed clinical manifestations of thyroid hyperfunction within a few days, with the appearance of antithyroid antibodies, despite being healthy before vaccination. Conclusion: Graves' disease can occur after SARS-CoV-2 vaccination.