Objectives: Lingual thyroid is a rare condition that affects approximately 1 in 100,000 individuals. Although it is usually detected in the pediatric population through newborn screening tests or evaluation of congenital hypothyroidism, there are cases in which it remains undetected until adulthood or until symptoms arise because of glandular enlargement. The possible symptoms of lingual thyroid include foreign body sensation in the throat, dysphagia, dyspnea, and hemorrhage. Several cases of lingual thyroid are asymptomatic and accompanied by subclinical hypothyroidism. Herein, we present three cases of lingual thyroid treated with thyroid hormone suppressive therapy. Case presentation: The three patients sought medical attention because of a sore throat or foreign body sensation in the throat. Their newborn screening tests and developmental histories were normal. These patients exhibited subclinical hypothyroidism and were treated with hormone suppression therapy. Conclusions: Patients with lingual thyroid frequently exhibit subclinical hypothyroidism. Hormone treatment may help to reduce the size of the ectopic thyroid and improve symptoms. If an increase in size is noted during follow-up or symptoms do not improve, surgical treatments may be considered.