Due to the value of teacher professional development in increasing student learning achievement, an increasing number of articles in general education have assessed the impact of this professional trait on student achievement. Nevertheless, in language education, a few investigations have examined the role of professional development in student learning achievement. Moreover, no inquiry has theoretically reviewed the implications of teacher professional development for EFL learners\' achievement. This theoretical review intends to address the gap by concentrating on the potential effects of teacher professional development on EFL students\' learning achievement. The empirical and theoretical evidence were thus inspected with a view to explaining the role of teacher professional development in English learners\' academic outcomes. Consequently, the prominent role of teacher professional development in improving EFL students\' learning achievement was proved using the relevant evidence. The present review\'s outcomes may be useful and illuminating for teachers, teacher educators, and educational managers.