During routine evaluation for lactation failure, hyperthyroidism was discovered in a postpartum woman. Although postpartum thyroiditis and Hashimoto's disease are relatively more common than Graves’ disease during the postnatal period, this young woman was found to have new-onset Graves’ disease. Distinguishing between normal postpartum symptoms and thyroid disorders can be challenging. Utilizing history, physical examination, and laboratory testing, the provider can identify the etiology of hyperthyroidism during the postpartum period. Treatment options differ depending on the cause of the thyroiditis and include antithyroid medications and beta-blockers for relief of symptoms.