The research aims to discover the roles of the teachers’ working group in improving professionalism of teachers of Islamic religion education (Research of KKG PAI in Kasihan sub-district). So that, this research described several points, namely the professionalism of Islamic religion teachers, the implementation process of teachers’ working group, the roles of those teachers in improving the professionalism. In addition, this research implemented qualitative method using several subjects, namely head of KKG PAI in Kasihan sub-district, supervisor of PAI in Kasihan sub-district, and teachers of Islamic religion education in elementary school as members’ representative of KKG PAI in Kasihan sub-district. Moreover, the process in data collection used interview, observation, and documentation method. Then, qualitative description applied in the analysis section. After conducting the research, researcher found that the existence of KKG resulted professionalism training with continuity to elementary teachers. Furthermore, it assisted teachers in dealing with their problems during their work such as creating syllabus and lesson plans, mastering the subject through discussion.