Perceived as the ability of teachers to shape their work conditions, enact pedagogical convictions, and resist restrictive discourses of power, teacher agency has been a focal research element in the teacher education literature. In line with such expansion of research on the concept, this chapter explores the construct of language teacher agency (LTA) and highlights its significance in fostering professional growth and promoting justice in educational contexts. Through a critical review of theoretical perspectives and an empirical synthesis of research conducted between 2010 and 2020, the chapter provides a thematic analysis of how LTA has been conceptualized and operationalized in recent studies. By synthesizing insights from a range of variables, including teacher identity, cognition, online instruction, and professional development, the chapter seeks to present a comprehensive understanding of LTA and offers suggestions for future research to build upon these findings.