This research seeks to understand how secondary science students make space for themselves in the classroom. Specifically, this study examines the interplay between classroom structures and students' agentic negotiations while identifying the relationship between students' enacted agency and their authored science identities by drawing from a sociological framework, structure-agency. An embedded case study was constructed from interviews, observations, and documents collected in a twelve-week Earth Science classroom. The collaborators involved in this study consisted of one monolingual science teacher and six linguistically diverse students. The findings reveal that students expressed agency in the classroom by challenging conventional pedagogical practices through direct negotiations with the teacher. This study highlights moments of student agency where they advocated for themselves and their peers to reshape classroom instructional and curricular structures for more active learning experiences. Structural constraints that shape the classroom space, influence teacher decision-making, and limit students' agency are exposed through data analysis. Science educators can reconsider their approach to instruction to cultivate inclusive learning spaces that value students' unique abilities and experiences by recognizing the nuanced reasoning for expressions of student agency. This study contributes to the evolution of science education by promoting strategies that prioritize student agency as a catalyst for meaningful instruction. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]