The purpose of this study was to investigate prospective middle school mathematics teachers' views on the flipped classroom. 41 third-year undergraduate students who were enrolled in the mathematics education department participated in this qualitative study. The study was conducted in the Statistics and Probability course and lasted for 11 weeks. Findings were organized under four themes as positive opinions, negative opinions, suggestions and the use of flipped classrooms in mathematics teaching. The findings showed that flipped classrooms had positive effects on prospective teachers' active participation in the lesson, self-regulation and teamwork skills. On the other hand, not making any revision of the subjects during the course and technical problems were found as the negative sides of the flipped classroom. The findings showed that it was important to establish a mechanism for arranging the self-regulation of students. In this context, Kahoot activities could be a useful way to make sure all students watch lecture videos before the class. It was also found that prospective teachers had different opinions on the use of flipped classrooms in mathematics teaching. Some prospective teachers would tend to use flipped learning when they start their careers for students to come prepared for the course and be responsible for their learning process. However, it was found that some prospective teachers would not implement flipped learning in their lessons since mathematics education should be only be carried out traditionally.