This research mainly discusses about the problem of self-assessment in the classroom with the percentage number 85%. Qualitative method is used to create this research with 29 srudents as its sample in XYZ Junior High School, Tangerang. There are three purpose of this research. First is to find out does self-assessment effective for students in junior high school level. Second is to evaluate how to conduct effective self-assessment. Third is to explore others thing that could be revealed from self-assessment. The important things that Christian teachers could do is to ressist the worldly paradigm and to lead students to grow independently for the sake of community. The results of this research are; self-assessment would be conducted effectively in junior high school level if and only with the supervision of the teacher; dig deeper the meaning of self-assessment, the importance of reflection, reflective thinking, reflective teaching, and its practice in education. Teachers need to adapt with improvements of technology. Then, teachers could conduct self-assessment in form of online assignment with the better file documentation. Teachers also may consider the best way in conducting effective self-assessment based on the seventh possibilities given.