The aim of this study is to examine the effect of classroom debate activities on the argumentativeness of Turkish language teacher candidates. The study group of the research consists of 29 freshman students in the Turkish Language Teaching program. Designed in mixed method, in this study Argumentativeness Scale and Semi-Structured Interview Form were used as data collection tools. The application process of the study took a total five weeks. For the analysis of the quantitative data which was obtained through the Argumentativeness Scale, the pre and post-test scores were compared using the t-test. However, at the end of the application, the opinions of the students were taken through the semi-structured interview form and these data were analyzed using the content analysis technique. As a result of the research, it was determined that there is a significant difference between the argumentativeness pre-test scores and post-test scores of the study group. The findings obtained from the interviews also confirmed that there is a difference in the argumentativeness of the teacher candidates. As a result, it was seen that classroom debate activities carried out in accordance with the rules can motivate prospective teachers to do discussions and reduce their anxiety and fear of discussions. In addition to this, according to the findings, debate activities encourage students to do research, create a competitive environment in the classroom and ensure active participation in the lessons. In line with the research results, suggestions for classroom discussion practices and suggestions for future research have been presented.