This systematic review tries to elucidate the association between what people know about HIV/AIDS and how they perceive their risk of infection. The initial search for articles yielded 1,595 abstracts, 16 of which met the inclusion criteria. Five studies found a positive correlation, four reported a negative correlation and seven found no association between knowledge and risk perception. It was found that the existing psychometrically sound measure of HIV/AIDS risk perception had not been used in any of the studies. The context in which the risk is assessed is pivotal to whether an association between knowledge and the perceived risk is found. Biases in judgement such as optimistic bias, psychological distancing, anchoring bias and overconfidence also explain how knowledge may fail to predict risk perception. It was concluded that the association between HIV/AIDS knowledge and risk perception might follow a continuum from positive to no association and finally to negative. The hypothesis, however, still needs to be studied further.