<p>Understanding the factors associated with students’ social and emotional skills is crucial for fostering well-rounded development and improving educational outcomes. This study examines the relationship between teacher professional development and students’ social and emotional skills, focusing on the potential mediating roles of teacher self-efficacy and teaching practices. Utilizing data from the Survey on Social and Emotional Skills (SSES), the sample includes 7,246 students and 3,624 teachers from Suzhou, China, targeting 10-year-old and 15-year-old students. The results suggest that teacher professional development is positively associated with students’ social and emotional skills, with teacher self-efficacy and teaching practices serving as significant mediators. Specifically, teacher self-efficacy mediates the relationship between teacher participation in professional development and students’ social and emotional skills. Additionally, student-centered teaching practices mediate the relationship between teacher participation in professional development and students’ social and emotional skills, as well as between participation in social and emotional skills training and students’ social and emotional skills. Furthermore, assessing student learning mediates the relationship between both types of teacher professional development and students’ social and emotional skills. Lastly, teacher self-efficacy and student-centered teaching practices act as sequential mediators in the relationship between teacher participation in professional development and students’ social and emotional skills, as do teacher self-efficacy and assessing student learning. These findings underscore the importance of comprehensive professional development programs that support teacher confidence and incorporate effective teaching and assessment practices, which may contribute to improved student outcomes.</p>