PURPOSE: An urgent need exists for training on men who have sex with men (MSM) health needs at public health clinics across Africa. There is also a need to consider the impact of specific training for clinicians and clinic support staff, both of whom come into contact with MSM. Consideration must also be given to the relationship between two key outcomes of such training: increased knowledge regarding MSM and their health and reductions in homoprejudicial attitudes. METHODS: This article explores the impact of training for clinicians and clinic support staff in the Western Cape, South Africa (n = 196), where some training modules were undertaken by both groups and some modules only by clinicians. Participants were evaluated at baseline and post-training on MSM knowledge and homoprejudicial attitudes. RESULTS: After training, both clinicians and clinic support staff showed an increase in knowledge and a reduction in homoprejudicial attitude scores, with similar proportional improvements for both groups. Additional trainings for clinicians also resulted in significant improvements in their knowledge. However, reductions in homoprejudicial attitudes were related to the type of knowledge obtained. A threshold effect in post-training knowledge scores of 9 or greater on sensitivity material significantly increased the likelihood of a reduction in homoprejudicial attitudes. CONCLUSION: These findings show that training for both types of clinic workers is important and effective, but facilitators should be mindful of complex relationships between knowledge and homoprejudicial attitudes.