Superficial palpable masses of the head and neck are common in the pediatric population, with the vast majority of the lesions ultimately proven to be benign. Duplex ultrasonography (US) has emerged as the first-line imaging modality for the evaluation of superficial pediatric masses. Without utilizing radiation, iodinated contrast material, or sedation and/or anesthesia, US provides a means for quick and cost-effective acquisition of information, including the location, size, shape, internal content, and vascularity of the mass. In this review, the US findings are described for a variety of common and uncommon pediatric head and neck masses diagnosed in our practice. Specifically, the entities covered include neonatal scalp hematoma, craniosynostosis, dermoid and epidermoid cysts, Langerhans cell histiocytosis, lymph nodes and their complications, fibromatosis colli, thyroglossal duct cyst, branchial cleft cyst, cervical thymus, congenital goiter, thyroid papillary carcinoma, parathyroid adenoma, hemangioma, lymphangioma, jugular vein phlebectasia, Lemierre syndrome, acute parotitis and parotid abscess, leukemia and/or lymphoma, neurogenic tumor, and rhabdomyosarcoma. Ultimately, in situations in which the head or neck mass is too large, deep, or hyperechoic to be fully assessed within the US field of view, or if malignancy or a high-flow vascular lesion is suspected, then further evaluation with cross-sectional imaging is warranted. Online supplemental material is available for this article. ©RSNA, 2018.