Objective: Posterior neck masses are a relatively poorly characterized entity. The authors attempt to further characterize the anatomy and pathology of the posterior neck by way of a combined single-institution retrospective chart review and systematic review of the literature. Methods: A single-institution retrospective chart review was undertaken for all patients undergoing excision of a posterior neck mass between January 1, 2012, and January 1, 2017. A systematic review of the Medline, Embase, Web of Science, and Cochrane database was undertaken in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in search of case reports and series describing posterior neck masses. Results: A total of 28 patients who underwent excision of a posterior neck mass were encountered during the retrospective chart review. All pathologies were benign, the most prevalent of which was lipoma (22/28, 79%). A total of 19 articles describing a collective 36 posterior neck masses were encountered during the systematic review. Lipomas were the most common pathology (15/36, 42%). All but one of the masses reported were benign (35/36, 97%). Conclusions: Patients presenting with posterior neck masses can be reassured of a low risk of malignancy. The majority of posterior neck masses can be appropriately evaluated via physical examination and ultrasound.