This paper reviews the current state of knowledge on age-disparate sexual relationships in the context of the southern African HIV/AIDS hyperepidemic. Disproportionately high HIV infection rates among young women aged 15-24 years have been attributed to their greater involvement in relationships with older-aged partners. Whereas early studies emphasized economic concerns in the context of poverty as driving girls to accept or seek the attentions of older employed men, close-grained studies reveal a complex interplay of meanings and motives that prompt both men and women across socioeconomic strata to engage in intergenerational sex. Studies have revealed that age-disparate relationships are meaningful and perceived as beneficial at a number of levels, including social, physical, psychological, as well as economic and symbolic. In the context of growing economic inequalities and cultural expectations for men to give and women to receive a compensation for sex, relationships with older men are a common and readily available way through which young women gain materially, affirm self-worth, achieve social goals, increase longer-term life chances, or otherwise add value and enjoyment to life. Awareness of HIV risks in these relationships remains low. HIV prevention policies and programmes need to start from an understanding of how those engaged in risky behaviour perceive their sexual relationships and conceptualize the choices they make and the strategies they use. A more comprehensive policy on women and girls with better integration of communities in assessing and addressing issues, and an expansion of campaigns and programmes on the role of men as protectors and supporters of women are recommended.