摘要：This study investigates the impact of Teacher Professional Development (TPD) on teaching quality and student learning outcomes. Utilizing a mixed-methods approach, the research draws on quantitative data from standardized test scores and qualitative insights from teacher interviews and classroom observations. The findings indicate a strong positive correlation between TPD, as measured by self-assessment and peer evaluation, and improvements in teaching practices. These enhancements in teaching quality are further shown to have a significant impact on student learning outcomes, including academic achievement, critical thinking, and engagement. The study also presents case studies that highlight the transformative potential of TPD in various educational contexts. Limitations include the generalizability of the sample and the correlational nature of the study design. The research concludes with policy implications, emphasizing the need for increased investment in TPD, customization of TPD programs, and the promotion of a collaborative culture within schools. Future research directions are suggested to further explore the long-term effects of TPD and the most effective models for professional development.