Teenagers experience a crisis of moral values such as honesty, justice, discipline, responsibility, wisdom, and fear of God. Teenager moral problems are a concern for parents, families, schools and society in general. Currently, the most important factor for students in schools is moral education. The presence of religious teachers in schools through Catholic religious education is very important for the moral development of students in dealing with this reality. This study aimed to determine the role of teachers in developing the moral values of class X and XI students at State Senior High School 1 Parbuluan. This study employs a qualitative methodology. Catholic Religious Education Teachers, Deputy Principals, and Students were interviewed for this study. The function of Catholic Religious Education Teachers in Developing Moral Values is to cultivate the spiritual, social, and behavioral attitudes of students. Teachers encourage and guide students to possess moral values like honesty, responsibility, justice, and discipline. Catholic teachers continue to have deficiencies in developing the moral values of their students, as evidenced by the fact that students are still tardy in entering and submitting assignments. Catholic teachers have not done their utmost to foster moral students, particularly in the application of honesty, responsibility, justice, and discipline. School conditions and situations have not maximally influenced the moral values of students. Recommendations for schools need to do character building education for students and moral education to become extra-curricular activities in schools.