This paper discusses the application of an information, motivation and behavioural skills (IMB) model in a school-based programme for the reduction of HIV risk behaviour among 259 Grade 11 learners in two high schools in Alexandra township, Johannesburg. School 1 was the Experimental group, while School 2 was the Control group. After a baseline study (Time 1) at both schools, a 3-week intervention programme was conducted at School 1. A post-test (Time 2) was conducted at both schools. The intervention was repeated at School 2, followed by another post-test (Time 3) at both schools. A final test (Time 4) was conducted at both schools. While there were positive changes in the levels of HIV&AIDS IMB in learner participants, these changes may not be entirely attributed to the intervention. If an IMB model-based intervention is to be maximally effective in reducing HIV-risk behaviour among adolescents, it must focus on the behavioural, structural and socio-cultural contexts in which adolescents live.