In this paper, we examine traditional psychosocial approaches to the study of student agency in science education, emphasizing the importance of incorporating sociocultural and critical perspectives. We present both contemporary studies of student agency in educational psychology and the work of scholars who study students' student agency with attention to the cultural, economic, political, and historical forces shaping agentic behaviors in schools. We overview conceptualizations of and evidence for fostering agency among historically marginalized students in science across three major theoretical frames (i.e., psychosocial, sociocultural, and critical). We end by calling for the expansion of psychosocial conceptions of student agency to underscore the role of complex classroom dynamics and to account for the historical exclusion of nondominant communities in science. Specifically, four principles for broadening the scholarship of student agency toward socially just goals are presented.