The aim of this study reveal the effect of philosophy education on students' mathematics achievement. The research sample consists of a total of 38 students, 18 of whom are experimental and 20 of them are control groups, studying in the 7th grade in Sehit Koray Akoguz Secondary School in Ipekyolu, Van in the second semester of the academic year 2019-2020. The mixed method was used in this study because the data of the research were collected both quantitatively. In the quantitative study part of the study, pretest and posttest quasi-experimental design with experimental and control groups was used, and special case design was used in the qualitative study. At the end of the application, individual interviews were made with 6 students in the experimental group using a semi-structured interview form. While in the analysis process of quantitative data independent groups t-test was used, in the analysis of qualitative data, codes were created and data were analyzed. In the process of collecting the data, the experimental group students were given speeches and discussions on philosophy related concepts in elective courses 2 hours a week for 8 weeks by the teacher of Religious Cukture and Ethics who was educated in the field of philosophy education and students were taught books on philosophy for children. Control group students continued with the normal curriculum in this process. An achievement test of 22 questions was developed by taking expert opinion after its validity and reliability were made by the researcher. The achievement test was applied to both groups as a pre-test before the application and as a post-test at the end of the application. In the analysis of qualitative data, a semi-structured interview consisting of 4 questions prepared by the researcher with expert opinion was applied with 6 students from the experimental group. As a result of the quantitative analysis, it was concluded that philosophy education had a positive effect on students' mathematics achievement. As a result of qualitative analysis, philosophy education improved students' sense of curiosity, helped in solving math problems, and improved students in reading comprehension. Also, another result is that students' interest in philosophy has increased.