Vietnam's increased integration into the global market economy entails rapid and dynamic changes that foster new ways of acting, interacting and rendering the world meaningful. This article addresses the ways in which an ongoing process of transformation in contemporary Vietnam is epitomised by the ambivalence and ambiguity with which female sexuality is imbued. Female sexuality is ideally restricted to marriage and motherhood, meaning that females' premarital or extramarital sexual relations tend to be associated with the category of 'social evils' (te nan xa hoi). The category of 'social evils' is vague in definition and was introduced into Vietnamese society by virtue of what was seen as the country's increased involvement in a morally polluted world. By drawing on two periods of fieldwork (1994-1995 and 2000-2001) in a northern rural Vietnamese commune, this article highlights the ways in which female sexuality in a local field site is intertwined with anxieties about the forces of a global and 'poisonous culture' (van hoa doc hai) that may lead young women to transgress moral limits: For example, by having premarital sex. For many rural female adolescents sexuality thus means a need of self-imposed and/or governmentally imposed control in order to guarantee appropriate morality. For others, however, sexuality means the involvement in premarital sexual relations and, hence, a crossing of moral boundaries.