The aim of this study is to investigate the effect of positive error climate in classrooms on middle school students' error orientations and attitudes towards mathematics. The data of the research were collected in the 2021-2022 academic year. The participants of the study consisted of 44 students in two 6th grade classes in a middle school in the city of Van, Türkiye. Quasi-experimental design was used in the research and the pre and post scores of the experimental and comparison groups were compared before and after the study. The data obtained using the "Mathematics Attitude Scale" and the "Error Climate Scale" were analyzed to examine the differences within and between groups. As a result of the findings, it was seen that the positive error climate in the experimental group made a positive significant difference both on the attitude towards mathematics and on error orientations of the students. No significant change was observed at the end of the study in the comparison group in which a neutral error climate was applied. The interviews with the course teacher who carried out the application and the observations made in the classroom reinforced the positive effect of the application. Positive error climate can be seen as a part of formative assessment as it has a corrective effect on teaching in the process.