There is an established international literature on the prevalence of non-suicidal self-injury (NSSI). However, New Zealand information regarding prevalence, attitudes, motivation, co-morbidities, etc., is limited. In this study data were collected using an on-line survey from approximately 850 university students regarding self-injurious behaviour, risk and protective factors, mental health co-morbidity, help-seeking, and addiction. Our data revealed that 293 participants (38%) had engaged in NSSI on at least one occasion in their lifetime, elevated risk for females who were lesbian or bisexual, and different patterns of site and function of injury by gender. Given research suggesting that Māori (indigenous New Zealanders) are at elevated risk for suicide it was surprising that those identifying as Māori were at no greater risk of NSSI than those identifying as New Zealanders of European origin. Females were more likely to exhibit chronic self-injuring and more likely to engage in more ‘covert’ forms of self-injury that can be hidden or disguised (e.g., scratching and cutting on their wrists, arms or thighs) whereas males were more likely to engage in ‘overt’ forms of self-injury (e.g., banging or punching themselves or objects with their hands or head). Patterns of NSSI were similar to international comparisons, although prevalence was somewhat elevated. A number of factors differed by gender, including underlying reasons, forms, rates and increasing severity of self-injury, which add to the international literature.