(1) Background: Primary hyperparathyroidism is a common disorder of the parathyroid glands and the third most frequent endocrinopathy, especially among elderly women. Secondary hyperparathyroidism is a common complication of chronic kidney disease, associated with high cardiovascular morbidity and mortality. In both primary and secondary hyperparathyroidism, the need to correctly identify the parathyroid glands is mandatory for a better outcome. Elastography can be an effective tool in the diagnosis of parathyroid lesions, by differentiating possible parathyroid lesions from thyroid disease, cervical lymph nodes, and other anatomical structures. There are currently no guidelines or recommendations and no established values on the elasticity of parathyroid lesions. (2) Material and Methods: In our studies, we have evaluated, by Shear Wave elastography (SWE), both primary and secondary hyperparathyroidism, determining that parathyroid glands have a higher elasticity index than both thyroid tissue and muscle tissue. (3) Results: For primary hyperparathyroidism, we have determined, using 2D-SWE, the parathyroid adenoma tissue (mean elasticity index (EI) measured by SWE 4.74 ± 2.74 kPa) with the thyroid tissue (11.718 ± 4.206 kPa) and with the surrounding muscle tissue (16.362 ± 3.829 kPa). For secondary hyperparathyroidism, by SWE elastographic evaluation, we have found that the mean EI in the parathyroid gland was 7.83 kPa, a median value in the thyroid parenchyma of 13.76 kPa, and a mean muscle EI value at 15.78 kPa. (4) Conclusions: Elastography can be a useful tool in localizing parathyroid disease, whether primary or secondary, by correctly identifying the parathyroid tissue. We have determined that an EI below 7 kPa in SWE elastography correctly identifies parathyroid tissue in primary hyperparathyroidism, and that a cut-off value of 9.98 kPa can be used in 2D-SWE to accurately diagnose parathyroid disease in secondary hyperparathyroidism.