Professional development (PD) is important in promoting educational reform achievements at many levels in all countries. In the last ten years, teacher professional development activities have received more attention and investment from the Vietnam Ministry of Education and Training, especially in the context of fundamental and comprehensive education reform. This study was conducted to identify the factors affecting the effectiveness of professional development for teachers, as manifested by the effectiveness of developing knowledge and skills or changes in teachers’ attitudes and beliefs in Vietnam. The study used a quantitative method. By stratified random sampling, 1,459 survey samples were collected from teachers working at the three levels of primary school, secondary school, and high school in Vietnam. The study’s findings indicate a substantial influence of all variables within the model on the enhancement of teachers’ knowledge and skills and alterations in attitudes and beliefs within the educational context of Vietnam. Notably, active learning and duration emerge as the two factors exerting the most pronounced impact on the efficacy of professional development for teachers in Vietnam. Based on these outcomes, the study provides insights and recommends policy adjustments tailored to the professional development needs of teachers in Vietnam.