This paper seeks to operationalise the concept of social "vulnerability" and explore its usefulness as a framework for understanding sexual relationships. Data from 30 vulnerable and less vulnerable young women in one UK city were collected through in-depth interviews and focus groups. An analysis of differences and similarities in participants' sexual relationships suggested that differences between the two groups of young women could be due to the divergent social contexts they lived in. Similarities in accounts offered, however, indicated that beyond vulnerability due to differences in socio-economic status, gender and other factors are crucial to any model for understanding young people's sexual relationships. The centrality of social context in differentiating between the experiences of different groups of young women, and the protection offered by environments that promote educational attainment and which are characterised by relatively high levels of adult supervision, is illustrated by two case studies of less vulnerable young women. (Contains 4 notes.)