Background: 'Transactional sex' was regarded by the mid-1990s as an important determinant of HIV transmission, particularly in sub-Saharan Africa. Little attention has been paid to what the terms used to denote transactional sex suggest about how it is understood. This study provides a nuanced set of descriptions of the meaning of transactional sex in three settings. Furthermore, we discuss how discourses around transactional sex suggest linkages to processes of globalization and hold implications for vulnerability to HIV.Methods: The analysis in this article is based on three case studies conducted as part of a multi-country research project that investigated linkages between economic globalization and HIV. In this analysis, we contextualize and contrast the 'talk' about transactional sex through the following research methods in three study sites: descriptions revealed through semi-structured interviews with garment workers in Lesotho; focus groups with young women and men in Antananarivo, Madagascar; and focus groups and in-depth interviews with young women and men in Mbekweni, South Africa.Results: Participants' talk about transactional sex reveals two themes: (1) 'The politics of differentiation' reflects how participants used language to demarcate identities, and distance themselves from contextually-based marginalized identities; and (2) 'Gender, agency and power' describes how participants frame gendered-power within the context of transactional sex practices, and reflects on the limitations to women's power as sexual agents in these exchanges. Talk about transactional sex in our study settings supports the assertion that emerging transactional sexual practices are linked with processes of globalization tied to consumerism.Conclusions: By focusing on 'talk' about transactional sex, we locate definitions of transactional sex, and how terms used to describe transactional sex are morally framed for people within their local context. We take advantage of an opportunity to comparatively explore such talk across three different study sites, and contribute to a better understanding of both emerging sexual practices and their implications for HIV vulnerability. Our work underlines that transactional sex needs to be reflected as it is perceived: something very different from, but of at least equal concern to, formal sex work in the efforts to curb HIV transmission.