The present small-scale study aimed to investigate teacher agency from the perspective of in-service language teachers in relation to their perceived professional space. It specifically aimed to have an understanding of factors contributing to teacher agency positively and negatively. To this end, eight Turkish EFL teachers working at private and state schools and various education levels were asked to reflect on their own perceived and exploited professional space in semi-structured interviews and storylines. The in-depth analysis of the data revealed three types of trajectories in agency: contested agency, gradual growth of agency and failure in achievement of agency. In these trajectories, it was found out that teachers' own motivation, material adaptation, cooperation of colleagues and technological equipment promote teacher agency, whereas some factors such as pressure from administration and parents, centralized curriculum and exams, workload and crowded classes serve as obstacles in the process. In line with the results, some implications for the development of teacher agency and also insights for teacher education programs were provided.