The aim of this study is to analyze the opinions of prospective teachers’ opinions on peer assessment. The research was conducted in Buca Education Faculty Primary School Mathematics Department, third grade course “Measurement and Evaluation in Education”. There were in 46 participants in the study (m=20, f=26). The study lasted for 5 weeks. The lessons were conducted according to cooperative learning method. At the end of sessions peer assessments were conducted and students’ written opinions on the implementation were received. Students’ responses were coded with Maxqda12 software program for qualitative research in order to analyze and organize the data. In the end two themes emerged. First were the positive and second were the negative opinions. The positive opinions were grouped under four sub-themes as accurate assessment, perform the task, rating learning, and confidentiality, whereas there were three negative sub-themes as reliability, impartiality, and concern.