The spectrum of congenital and infantile masses of the head and neck is broad, including developmental and neoplastic entities. The diseases encountered in this vulnerable patient population differ substantially from those in older children and adults. Familiarity with the types of encountered masses, typical imaging characteristics, and expected clinical course is critical for radiologists who care for pregnant women (fetuses) and infants. This knowledge allows radiologists to provide a timely diagnosis and appropriate follow-up imaging recommendations and, in some fetal imaging cases, inform delivery planning. This article uses a location-based approach to highlight imaging features of numerous common and rare congenital and infantile masses of the head and neck. ©RSNA, 2024 Supplemental material is available for this article.