The thyroid plays a major role in growth and development, and the hormones it produces can affect many different systems of the body. For this reason, the thyroid should always be at the front of our minds when evaluating children and adolescents. The symptoms of thyroid abnormalities can often be subtle and evolve over time, so we must have a high index of suspicion when providing care for our patients. It is important to understand what can go wrong with the thyroid, how to diagnose thyroid disease, and how to manage thyroid abnormalities. Whether it is structural changes in the thyroid such as goiter or nodules, functional changes that lead to hyperthyroidism or hypothyroidism, or thyroid cancer, a thorough examination and appropriate treatment is essential to maintain optimal cognitive and physical growth throughout childhood and adolescence. This article will discuss the most common thyroid abnormalities, how to diagnose them, and how to treat and manage them in both the short and long term. [Pediatr Ann. 2021;50(4):e143-e147.].