Background. Young people grow up in homes and communities where many are exposed daily to crime and antisocial behaviours. Objective. To investigate the prevalence of violence and the demographic factors associated with such violence among South African (SA) high school learners in the uMgungundlovu District, KwaZulu-Natal, SA. Methods. In a cross-sectional study, we used stratified random sampling to select 16 schools in uMgungundlovu District. All Grade 10 high school learners (N=1 741) completed a self-administered questionnaire (Centers for Disease Control Youth Risk Behavior Survey). Data analysis was carried out using STATA 13 statistical software (Statacorp, USA). Results. Of the participants in this study, 420 (23.9%) had been bullied, 379 (21.7%) had missed school because of feeling unsafe, 468 (15.4%) had been involved in physical fights and 41 (2.4%) had carried weapons to school. There was a significant association between being in a physical fight and missing school (odds ratio (OR) 2.5, 95% confidence interval (CI) 1.9 -3.3; p<0.001). There were higher odds of male learners carrying weapons than female learners (OR 5.9, 95% CI 2.0 -15.0). Among learners living in rented rooms, the OR of feeling unsafe was 2.7 (95% CI 0.8 -3.0), in an informal settlement the OR was 0.8 (95% CI 0.3 -2.0) and in reconstruction and development programme houses it was 2.7 (95% CI 1.0 -5.0), compared with learners residing in Zulu homesteads. Conclusion. Violence among learners attending high schools in uMgungundlovu District is a major problem and has consequences for both their academic and social lives. Urgent interventions are required to reduce the rates of violence among high school learners.