The Arthur Waser Foundation enables teacher trainers at Montessori training centers to acquire in-depth specialist knowledge in the field of early childhood education. In the Global South as much as in the Global North, the quality of education provided in kindergartens largely depends on how well trained the teachers are. In Tanzania, prospective Montessori kindergarten teachers have to complete two- to three-year programs at a Montessori training center. The teacher trainers at Montessori training centers themselves must be well trained so they can offer high-quality courses to prospective teachers. In cooperation with Association Montessori Internationale, the Arthur Waser Foundation organizes international diploma courses in Tanzania for these teacher trainers. After completing the course, the teacher trainers apply their in-depth knowledge in the respective teacher training centers.