<p>Understanding how teaching quality influences student achievement offers insights for the design and implementation of professional development programs. Drawing from an adapted version of the Dynamic Model of Educational Effectiveness for the Taiwanese educational context, this study aims to investigate the relationship between teaching quality and student outcomes in Taiwan. Data for this study were collected through a questionnaire and mathematics tests, involving 55 Taiwanese primary school teachers and 1480 students. Teachers were classified into three stages of teaching quality, which were then linked to students’ mathematics performance. Results showed that students taught by teachers in the highest-quality teaching stage generally achieved higher final mathematics scores, regardless of their initial performance. The study also reveals that students’ initial mathematics performance and socioeconomic status (SES) are significant predictors of their final mathematics outcomes. The outcomes highlight the necessity of considering cultural and contextual factors when identifying stages of teaching quality. Additionally, the findings reaffirm that teaching quality is an important factor in student achievement, as students in high-quality learning environments tend to achieve better academic outcomes. Suggestions related to teacher professional development are proposed, encompassing the development of a student feedback instrument to support teachers in optimising the quality of their teaching and enhancing the overall learning environment.</p>