The research aims at finding out how the development of social learning model based on metacognitive strategies or PS MEDIM model fosters the mathematics self-efficacy of students which is valid, practical, and effective. In order to obtain the valid, practical, and effective model, instruments and learning tools are well developed. The product of this research is a social learning model based on metacognitive strategies that can foster self-efficacy in mathematics. The development is conducted simultaneously. When developing the model, instruments and tools that support learning model of PS MEDIM are also developed. This research is research development (developmental research) which refers to the modification of the development of Tjeerd Plomp model with 4 phases of development. The first phase is a preliminary investigation. The second phase is designing. The third phase is realization. The fourth phase testing, evaluation, and revision. There is also a trial test of PS MEDIM learning model that is conducted in class XI IPA1 and XI IPA2 of SMAN 9 Makassar. There are some results of the research. First, the model, instruments, and the learning tools of PS MEDIM are valid. Second, the model of PS MEDIM is eligible to apply in the classroom. Third, the model of PS MEDIM does not meet the criteria of practicality. It indicates that the components of the model of PS MEDIM has not been implemented as expected and does not meet the criteria of effectiveness. From 4 criteria of effectiveness, there is only one criterion fulfilled. The students’ positive response to the learning model of PS MEDIM, and other three criteria have not been met. The classical completeness is not reached. The student's activity has not been as expected. In addition, the teacher's ability for teaching and learning management is still in “medium” category.