<p>The investigative aim of this thesis is to explore the role of language in the construction of sexuality agency during a classroom-based sexuality education programme for adolescents. The thesis begins with an examination of the motivations behind the study of agency in relation to sexuality. Overlapping research gaps in the fields of language and gender/sexuality and sexuality education are identified. Scholars from both fields have pinpointed difficulties with the accessing of agentive sexual subject positions by young people (particularly young women) during conversation. Investigations into sexuality education in New Zealand have suggested that ‘Discourses’ of sexuality in classrooms and broader school communities position students as ‘sexual’ while simultaneously constructing them as innocent and childlike (and thus non-sexual). These ‘large-D’ Discourses have been identified as possible reasons for a lack of decline in the rates of pregnancy and sexually transmitted disease amongst young people despite an overt focus on such topics in sexuality education. The theory is that because they have not developed a sense of agency in relation to sexuality, young people are ill-equipped to navigate the risks of sexual activity. A question which remains is exactly how sexual agency is negotiated through ‘small-d’ discourse (e.g. ‘talk’), by young people in classrooms. This study focuses on language usage during classroom discussions of sexuality in order to shed light on linguistic strategies that young people employ in order to position themselves (or not) as sexual agents during sexuality education, and how they respond to being similarly positioned, both by others and by their classroom resources. In order to gain an understanding of the working dynamics of the school and classroom, an ethnographic approach was employed. The researcher participated in classes for a period of time before the sexuality programme began in order to observe relations between the participants, including the distribution of power amongst teacher and students. These observations were essential to comprehending the understandings that participants bring to the processes and activities under study. This approach also permitted the tracing of the emergence of a community of practice in this classroom. Through close attention to language via poststructuralist discourse analysis, it has been possible to demonstrate how interactants performatively lay claim to (or avoid) sexual agency in this community of practice. By actively participating in discussions of sexuality, the students, both boys and girls, experience being placed in sexually agentive subject positions. They respond in various ways; sometimes aligning, sometimes resisting, other times resignifying those positions in complex interactions of masculinity, femininity, desire, and sexual identity. Finally, the findings of this thesis are assembled in order to consider implications for the study of language and sexuality as well as considering the importance of discursive positionings (by teachers and classroom resources) for future student possibilities in terms of sexual agency development.</p>