This study investigated the effects of a HIV/AIDS module on teachers' sense of self-efficacy regarding their ability to bring about behaviours in their learners which contribute to responsible living and a reduction of the spread of HIV in their communities. The sample was 128 in-service teachers studying in nine different centres in three South African provinces in their second year of a part-time degree in education. A modified Science Teaching Efficacy Belief Instrument (STEBI) was used to generate quantitative data, while semi-structured individual and focus group interviews provided qualitative data. Statistical analyses (ANOVA and MANOVA) revealed statistically significant differences between the participants pre- and post-test self-efficacy scores. Interview data suggested that improved confidence enabled the teachers to gain a better understanding of cultural barriers to HIV/AIDS education and the impediments to developing an effective HIV/AIDS policy in their schools. The study also highlighted the importance of leadership from school management for the successful adoption and implementation of an effective HIV/AIDS policy in schools. Enhanced confidence is noted as a motivating factor for teacher participation in community efforts to support those affected by HIV/AIDS.