The purpose of this research; was aimed to determine the opinions of middle school mathematics teachers regarding the High School Entrance Exam (LGS), which was put into practice in 2018, according to the demographic characteristics of the teachers. In this study, in which quantitative research approach was adopted, the relational screening model was used. This study was carried out with 471 middle school mathematics teachers who are working in different regions of Turkey. In the study, the data collection tool, consisting of 23 questions, was developed by the researcher. As a result of the study, the most accepted opinions by the teachers are that LGS system increased the need for self-renewal and development of the teachers and the visualization of the questions facilitated the students' understanding. Among the least accepted opinions by teachers, it was determined that the questions were similar to the written exam questions, the duration of the exam was sufficient for solving the questions, the questions were aimed at measuring the knowledge level of the students. Finally, LGS system increased the competition among students.