The present study analyzes the relationship between attitude and performance of 15-year-old students in Ecuador in the area of Mathematics, based on the PISA-D database of the Organization for Economic Cooperation and Development, and focus groups with secondary school teachers. For this reason, the mixed sequential exploratory method was used with a predominance of the quantitative approach. The sample was 12 teachers, 5,664 students and 173 Ecuadorian educational centers. The data collection instruments were focus group guides, context questionnaires and cognitive questionnaires. The main results show that there is a direct relationship between the attitude and performance of students in the area of Mathematics both at the individual level and at the school level, causing a greater impact on the latter. Likewise, the results show that the possible causes that give rise to a type of attitude are due to the student’s behavior, classroom discipline and the role played by the teacher in the classroom. Furthermore, it is recommended that teachers consider this factor when carrying out their educational practice, have a closer relationship with the student and work collaboratively with the educational members to promote a positive attitude in the students so that they can recognize the value and importance of learning and application of Mathematics both in the present and in the future.