This developmental research aimed at producing a model of mathematics instruction utilizing the community social system. The research population was Grade VII students of State Junior Secondary Schools in South Sulawesi Province from which 12 classes in 6 disctricts were drawn as the research sample using the purposive random sampling technique. The data were analyzed using the descriptive qualitative analysis. The yielded products included the book of the instructional model and the supporting package for the instruction, namely, lesson plans, student books, student worksheets, and achievement tests. The research findings were: (1) the validation processes covering all aspect/components revealed that the model was valid; (2) theoretically, the instructional model was considered feasible to be applied in the classroom setting; while empirically, the model satisfied the criteria of being practical and effective, and it, therefore, could be implemented at schools.