Intrathyroidal ectopic thymus (IET) is defined as an ectopic thymus tissue that is generally found incidentally and rarely in the thyroid gland in the pediatric group. It occurs as a result of disruption of the embryological migration path and the settling of the thymus tissue into the thyroid gland. In the differential diagnosis, it is mostly confused with thyroid nodules. Although thyroid nodules are less common in children than adults, the rate of malignancy is much higher. Therefore, knowing the general ultrasound findings of IET better may prevent unnecessary invasive attempts and surgical procedures. In this article, we tried to compile the key imaging findings of IET.