The purpose of this study is to investigate the effects of students‟ attitudes towards the mathematics classes and mathematics teacher on the student‟s math‟s achievements. The participants of this study were 44 (9. 10. 11. and 12. grade) public high school students at an Anatolian city Isparta. An attitude inventory was used to measure the participants‟ attitudes towards the lesson and teacher. Students‟ academic success levels were determined using participants‟ grades at the end of first semester. Scores obtained from the attitude inventory were categorized by the experts. Finally, by using fuzzy logic modeling, the cases in which the minimum and maximum achievement level occurs are determined.