Recent research on adolescent sexual intercourse has focused on attempts to identify factors that contribute to the onset of early sexual activity. To date, information generated from such research includes very little reference to teenagers' perspectives of their behaviours or consideration of sexual behaviour within a broader life context. This thesis aimed to provide a better understanding of teenage sexual intercourse because it involved direct discussions with teenage girls about their unplanned sexual intercourse (USI) experiences. The participants in this study were 22 sexually active teenage girls (aged 14-17 years) referred by health professionals working in a high school health centre in Christchurch, New Zealand. The study involved holding semi-structured interviews with the girls, about their experiences of sexual intercourse and transcribing and analysing the interviews using established qualitative methods such as constant comparative method and typology construction. A developmental framework incorporating Bronfenbrenner's (1979) bioecological model and sociocultural approaches to development was employed to explore the complexity and diversity evident in the girls' narratives. These narratives provided detailed descriptions of the girls' perceptions of their early sexual experiences, including first sexual intercourse (FSI), subsequent sexual intercourse (SSI) and their most recent unplanned sexual intercourse (MRUSI). A protective discourse and erotic discourse featured prevalently in the girls' talk. Of particular importance were: the girls' diverse interpretations of these discourses; the range of factors that motivated sexual intercourse; the girls' perceptions of parents' views of teenage sexual intercourse; and the girls' analysis of their sexuality education. While the content of the girls' interpretations supported findings of previous research in the area, they also extended our knowledge by providing alternative ways of looking at factors commonly associated with teenage sexual intercourse. Implications of these findings include the need for researchers and people working with teenagers to broaden their views of adolescent sexual activity and to incorporate alternative perspectives on teenage sexual intercourse. Future research in the area should foster strategies that ensure that diversity in adolescent sexual experience and understanding is solicited, acknowledged, and promoted.