This research was conducted to examine the applicability of the dialogic approach in teaching the subject of quadrilaterals to 5th grade students. The participants of the research are three students studying in the 5th grade of a public school in Ortahisar district of Trabzon province in the 2021-2022 academic year. In the research in which the case study method was adopted, the course process, which was taught in accordance with the dialogic approach with the students, lasted for three weeks. “Creating a diagonal scenario”, “change the position of the quadrilaterals”, “painting”, “secret grouping activity, “create a particular group of quadrilaterals analogous to the map of Turkey” activities were done in the lesson. Video recordings, teacher diaries and student diaries were used in the research. The obtained data were analyzed with descriptive analysis method and interpreted according to Alexander’s (2010) dialogic teaching principles "collectiveness", "reciprocity", "supportiveness", "cumulativeness" and "purposefulness". Data diversity was ensured through data triangulation to increase the validity and reliability of the study. The lessons taught with the dialogic approach took longer than the traditional method because they are designed according to the student's responses. In this approach, the student felt valued, active and satisfied with the application. From the teacher's point of view, the dialogic approach allowed the student's misconceptions to be accurately identified and also provided the opportunity to immediately resolve those misconceptions by creating a cognitive conflict. Although in the early days, it could be seen that the teacher could not break away from the traditional teacher role and presented prefabricated answers without directing the dialogues, she later adapted to her new role. She managed to conduct the dialogues under Alexander's principles. At the end of the research, it is recommended to create discussion environments in order to increase the questioning skills of the students. Books can be prepared, and teacher training on the dialogic approach can be conducted. This study can be conducted in crowded classrooms by enriching them with technology. In this way, time can be saved in conducting the activities.

Dialogical approach, mathematics teaching, special quadrilaterals, 5th grade students