Thesis (Ph.D.(Educational Psychology)) --University of Limpopo, 2015. / The aim of this study was to adapt an HIV and AIDS intervention programme that may change the knowledge, attitudes and behaviour of adolescents in Mpumalanga high schools. Mixed-method of qualitative and quantitative designs were used to achieve the objectives. The qualitative design consisted of peer mentors (N=141) who were interviewed in the focus group to provide information pertaining to the HIV and AIDS intervention that may change the knowledge, attitudes and behaviour of vulnerable adolescents in Mpumalanga high schools. The quantitative design consisted of Grade 8 learners (N=1 085) who were used in the evaluation of the adapted HIV and AIDS intervention. Eeducators (N=11) piloted and monitored the administration of the adapted HIV and AIDS intervention. Results from the qualitative study suggested a four unit HIV and AIDS intervention programme with the following aims: (a) to empower adolescents to respond to risky behaviours, (b) to enable adolescents in Mpumalanga to acquire necessary knowledge, attitudes and skills that will protect adolescents from HIV and AIDS infection, (c) the programme must also aim at the development of self-in-society and (d) an abridged programme that will run for one school term that is more suitable. Results from quantitative evaluation revealed that the adapted HIV and AIDS intervention managed to increase, slightly, the acquisition of the knowledge and behaviour of participants, although the significant tests indicated that the observed rate of increase was statistically not significant at 0.05 levels. No impact was found on attitudes scales. It was recommended that the support of both adolescents and parents is vital for the success of any of any HIV and AIDS intervention programme. Opening of the community youth friendly health clinics with highly trained practitioners was also recommended as an essential element in HIV and AIDS prevention. Key concepts: Adolescents, Attitudes, Behaviour, HIV and AIDS intervention, Knowledge and Knowledge attitudes-behaviour practices.