This study examines the role of workplace professional development in enhancing the instructional effectiveness of physical and health education teachers and itssubsequent impact on student physical literacy, particularly during the transition to the International Baccalaureate (IB) Middle Years Programme (MYP). The research aimed to assess how targeted professional learning initiatives influence teaching performance and foster physical literacy among students. Data were collected from a sample of three physical and health education teachers and 128 MYP Year 1 students, selected from a total population of 391 students across MYP Years 1-4. Quantitative analysis revealed a statistically significant improvement in students' physical literacy after one academic year, with notable differences between Unit 1 and Unit 2 test scores (M = -3.625, SD = 3.76473, t(127) = -10.894, p < 0.000). Improvements included increased physical fitness, enhanced self-confidence, and a deeper understanding of healthy lifestyle practices. The findings provide evidence that comprehensive, context-specific professional development can significantly improve teaching quality and positively influence student outcomes in physical education. The study recommends fostering a collaborative school culture that supports ongoing communication and professional growth tailored to educators' needs. The results of this current study will contribute a useful framework for fair and scalable professional development, giving teachers, school leaders, and policymakers who want to improve teaching quality in difficult situations useful information.