The aim of this study is to compare the mathematics teacher training processes of Turkey, Singapore and the Netherlands in the context of prospective student selection, training programs, employment conditions and in-service training. Countries have been selected due to their success in PISA exams, and the processes of achieving success in teacher education of different approaches in training field teachers have been examined and compared with our country. The study is a comparative education research and horizontal comparison approach was used. In addition, the study was designed with an intertwined multiple-case pattern, one of the qualitative research methods. The data of the study were obtained by examining the teacher training programs of the countries compared, the curricula reflecting their systems, and the comparative education studies covering these countries. In the findings of the study, it was seen that the planning and criteria for the selection of pre-service mathematics teachers contributed to the qualified teacher training process in Singapore. In addition, making a postgraduate selection in the Netherlands also contributes to the selection of students with high field knowledge. While mathematics teacher training programs in Singapore and Turkey focus on similar fields, they differ in the Netherlands as they are at postgraduate level. While the employment problem progresses centrally and smoothly, since teacher prospective students are selected according to needs in Singapore, the elimination process in Turkey at the end of the undergraduate education brings employment problems with it. In the Netherlands, there is a local recruitment system. The importance given by countries to in-service training is high and similar. In this context, various suggestions have been made, taking into account cultural elements.