Turner syndrome is a hereditary chromosomal anomaly that affects girls and women. A result of gonadal dysgenesis, its primary characteristics are short stature, osteoporosis, neck webbing, and cardiac defects. Turner syndrome may also involve the auditory system and kidneys. We report the case of a woman with Turner syndrome who presented late in adulthood with severe osteoporosis and hypercalcemia. She was subsequently diagnosed with primary hyperparathyroidism secondary to a parathyroid adenoma. After excision of the adenoma, the woman's serum calcium level normalized. To the best of our knowledge, only 4 other cases of Turner syndrome with hyperparathyroidism have been reported in the literature.