Available online 18 December 2010. Objectives. To collate and appraise incidence and severity data for neck injury in Rugby Union. To report risk factors for neck injury in Rugby Union that are supported by incidence and severity data. Design. Systematic review. Methods. Original journal articles were retrieved from electronic searches of AusportMed, AUSPORT, Scopus, Medline (Ovid), CINAHL, Mantis, and Pubmed databases and relevant bibliographic hand searches. Selection criteria were restricted to: (a) prospective study designs including cohort, case–control, and intervention methodologies; (b) populations of Rugby Union players, either male or female of any age; (c) studies must report on neck injury incidence and/or severity specifically; (d) articles with republished neck injury data were excluded. The STROBE Statement was adapted for the quality assessment of included studies and categorised as either poor, moderate or good. Results. Thirty-three original articles met the selection criteria. Wide variation of injury and exposure definitions and population sampling was identified in the included articles. Neck injury incidence ranged between 0.26 (CI: 0.08, 0.93) and 9.17 (CI: 1.89, 26.81) per 1000 player hours for mixed populations that adopted an all inclusive sports injury definition. There is a paucity of severity data and analytical data which evaluates causal roles of risk factors for neck injury in Rugby Union. Conclusions. Meaningful understanding of neck injury incidence and severity in Rugby Union is restricted to a few studies which adopt comparable methodological construct. This paper provides an index for future neck injury studies in Rugby Union.