Akosah, Ernest FrimpongArthur, Yarhands DissouObeng, Benjamin Adu2025-07-152025-07-152025Akosah, E. F., Arthur, Y. D., & Obeng, B. A. (2025). Optimizing high school mathematics achievement through the lens of realistic mathematics education: The mediating role of teacher self-efficacy. International Journal of Studies in Education and Science, 6(2), 192-211.https://ir.aamusted.edu.gh/handle/123456789/112This study examines the relationship between teaching quality, teacher self efficacy, and students' mathematics achievement among junior high school students in Ghana, utilizing Realistic Mathematics Education and Self Determination Theory as frameworks. A stratified purposive sample of 507 junior high school mathematics teachers from eight regions was selected, employing a correlational cross-sectional survey design. Structural Equation Modeling (SEM) tested the hypotheses that teaching quality positively affects mathematics achievement, teacher self-efficacy influences teaching quality, and self-efficacy mediates the relationship between teaching quality and achievement. Results confirmed that high-quality teaching significantly improves mathematics achievement, especially when contextualized with RME principles. Teacher self efficacy emerged as a critical factor in enhancing teaching quality and directly influencing student outcomes. Mediation analysis showed that teacher self efficacy strengthens the effect of teaching quality on achievement. These findings highlight the need for educational policies to focus on professional development that boosts teachers' efficacy and promotes realistic, student-centered instructional strategies.enMathematics achievement Realistic mathematics education Self-Determination Theory Structural equation modeling Teaching quality Teacher self-efficacyArticle