This study aims to; 1) investigate and analyse the role of ISMUBA teachers in improving students’ discipline in attending congregational prayer in SMK Muhammadiyah 1 Bantul; 2) investigate the students’ attitude toward the teachers’ effort in improving the discipline of the tenth-grade students in SMK Muhammadiyah 1 Bantul; 3) identify and analyse the hindrance faced by the ISMUBA teachers in improving students’ discipline in attending congregational prayer. This study is a qualitative research using descriptive approach. Data sources are the ISMUBA teachers, the tenth-grade students, as well as relevant documents from the school’s archive. The data are collected through interview, observation, documentation. The collected data then analysed by using a method which consists of several steps, including; data organization, recognizing patterns, and drawing conclusions. The result of this study shows that; (1) there are four roles played by the ISMUBA teachers in improving the students’ discipline, namely; the first, giving guidance, motivation and supervising the students when attending congregational prayer in mosques. The second, teachers rise the students’ awareness and understanding about the importance of attending congregational prayer through oral presentation, discussion, or by utilizing educational videos, they also demonstrate how to do congregational prayer. The third, the teachers give punishment to any students who break the rules. The fourth, the ISMUBA teachers act as good role models to their student in attending congregational prayer. (2) The students’ attitude toward the teachers’ efforts can be classified into three categories, namely; the first some students do not fully follow the teacher’s command and do not have the awareness to go to the mosques (to attend congregational prayer) immediately; the second, some students still do not have proper understanding of the rules of congregational prayer, and the third, some students do not pay attention to the teachers at all; (3) the supporting factors that help the teachers’ effort are good infrastructures, their competency, and good collaborative efforts with GerakanKedisiplinanSekolah(GDS) personals and the School Counsellor (BK). Whereas the hindrance faced by the teachers are lack of support from other teaches, other than GDS and BK, 3 disproportionate student-teacher ratio, and the ineffective punishment which do not prevent students from breaking the rules repeatedly.