Objective - This study aimed to assess the reliability of an adaptation of the Harvard Trauma Questionnaire for use in epidemiological investigations of adolescents' exposure to violence and related post-traumatic stress disorder (PTSD) symptoms. Method - The exposure items of the Harvard Trauma Questionnaire were adapted for the South African context. The symptoms scale was left intact. Self-report questionnaires were administered on two occasions to 104 students in four high schools in Cape Town, South Africa. Test-retest reliability was assessed using Cohen's kappa (k) and observed agreement, as well as a concordance correlation coefficient for the symptoms scale. Cronbach's alpha was used to assess internal consistency of the symptoms scale. Results - All but one item showed at least fair test-retest reliability. Cronbach's alpha for the symptoms scale was 0.92, and the concordance correlation coefficient between the total symptoms score at time 1 and time 2 was 0.64 (95% CI = 0.51-0.74). Conclusions - Results suggest that the instrument may be sufficiently reliable for use in epidemiological studies of adolescent populations, although this sample is limited in several key respects. Further studies should investigate reliability in broader samples, as well as examining validity.