Thyroid diseases are one of the most frequently found disorders of the endocrine glands, second to diabetes. Thyroid hormones play an important role during every stage of a child’s development. They regulate cell metabolism and heat production, as well as affect the development and maturation of many tissues, including the central nervous system and the skeletal system. Many symptoms of thyroid d ysfunction can be seen during a visit to the dentist’s office. Thus, through knowledge of clinical symptoms of thyroid disease, the dentist may play a role in the diagnostic process. Moreover, the awareness of the patient’s metabolic status and the cours e of current therapy are important for conducting safe dental procedures. Dental treatment of patients with balanced thyroid function is relatively safe. However, particular caution and consideration of the modification of therapy are required for patients with clinical and laboratory thyroid dysfunctions. In such cases, cooperation between the dentist and the endocrinologist is very important. This paper presents symptomatology, including oral symptoms, of hypothyroidism and hyperthyroidism in children and adolescents, as well as general principles of dental care for a patient with thyroid dysfunctions.