This study is a Research and Development (R&D) study developed by Borg and Gall, aiming to design a model for Internal Supervision in Educational Fund Management at the First-Level Middle School (SMP) in Mamuju Regency. The aspects discussed are the consulting aspect with indicators of socialization of School Operational Assistance (BOS) funds and community complaint services. The internal control system aspect of educational units (SPISP) with indicators of planning, process, and evaluation. The assurance aspect with indicators of review and audit. The research location is all SMPs in Mamuju Regency, consisting of 65 schools, and 30 school principals were selected as respondents. The research data was obtained by providing instruments/ questionnaires through focus group discussions (FGD) with the SMP School Committee, with emphasis on the pre-test and post-test processes. The data analysis technique used is descriptive quantitative and qualitative statistics, as well as N-Gain increase analysis, which shows that the effectiveness of this model design is quite effective with a value of 0.7.