Central exams which are reflection of structure of education systems determine many schooling processes. Especially, scores coming from these exams are indicators for student performance. Transition to upper-secondary school from lower-secondary school is based on "System of Transition to Upper-Secondary Schools" (LGS). The current study aimed to examine the relationship between scores on System of Transition to High Schools (LGS) and student, classroom, and school level variables. The design of the study is a correlational research. The random sample consisted of 731 students from 47 classrooms in the 15 lower-secondary schools. Secondary data coming from educational institutions via school information form were analyzed by Hierarchical Linear Modelling (HLM). School success score as a student-level variable, experience of a class teacher as a classroom-level variable, and a number of exam branch teachers, and a number of teachers assigned in support and training courses as school-level variables predicted significantly students' performance in LGS. Considering the results of the current study, activities for professional development of teachers is recommended urgently to increase performance of the students.