Hyperthyroidism is relatively uncommon during pregnancy. However, those caring for pregnant patients should be versed in the evaluation and management of hyperthyroidism, as there are potential maternal and fetal implications that are related to the disease and to treatment. The differential diagnosis of hyperthyroidism includes clinical and subclinical entities, as well as transient laboratory findings that are related to the pregnancy itself. The clinical management, including the indications for the use of thioamide or antithyroid medications, will be discussed in the context of pregnancy. Finally, considerations for the management of the postpartum and/or breastfeeding patient with hyperthyroidism will be reviewed.