The aim of this study was to determine the predictive and explanatory relationship model between the academic performance of university prep school students and the level for their motivation, anxiety and attitudes. A total of 631 university students formed the study group. To determine the students' motivation, 'Academic Motivation Scale'; to find out their anxiety level 'Foreign Language Classroom Anxiety Scale' and for their attitudes 'Questionnaire on Attitudes towards English' were applied. The students' grades in the autumn term were taken into account as indicators for the academic performance. The data gained through the research were 66 Öğr. Gör. Uğur AKPUR / Yrd. Doç. Dr. Bülent ALCI analyzed by using SPSS 21.0 and AMOS 22.0 software program through Structural Equation Model (SEM). At the end of the research, the model which was first suggested for the test was analyzed, tested and verified after some modifications suitable with indexes. The results indicated that there was a negative and significant relationship between attitudes towards English and foreign language classroom anxiety; extrinsic motivation and foreign language classroom anxiety; and intrinsic motivation and foreign language classroom anxiety levels. However, it was found out that, there was a positive and significant relationship between students' attitudes towards English and intrinsic motivation; their extrinsic motivation and attitudes towards English and their intrinsic motivation and extrinsic motivation levels. In addition, unlike anxiety levels, students' attitudes towards English, intrinsic and extrinsic motivation levels had a significant power to predict academic performance. In the light of the findings, the relationship pattern between English prep school students' academic performance and their motivation, anxiety and attitudes was suggested as a model.