Practitioner research features highly in Thailand’s teacher education policies but its purpose and significance remain less understood among student teachers, teachers, and teacher educators. This paper reports a study on the institutional foundation of research-based teacher education in Thailand. Content analysis of the related laws, regulations, and professional standards revealed that teacher professional standards were revised in 2013 and 2019. Notably, the latest teacher professional standards consolidate existing standards into one standard, thereby reducing the number of standards. Compared to the previous two versions of the professional standards, there is a remarkable increase in the listed competences. Despite these changes in professional standards, improving teaching and learning consistently features as the purpose of practitioner research. By making more explicit the purpose of practitioner research, this study offers the potential to understand how research-based teacher education can be improved at system level.