The objective of this study is to identify the factors affecting financial Supervision of the budget with an internal supervision approach in Iran's public sector using the meta-synthesis method, a type of meta-study. This research analyzes previous findings and applies the seven-step method of Sandelowski and Barroso to categorize the conceptual model of factors influencing financial Supervision of the budget with an internal supervision approach. Using three-stage coding in MAXQDA software, these factors were analyzed and categorized into 8 dimensions, 27 components (concepts), and 86 indicators. The study employed the Kappa coefficient method to assess reliability and quality control, with the SPSS-calculated Kappa coefficient of 0.771 indicating a valid level of agreement. The results show that the factors influencing financial Supervision of the budget with an internal supervision approach include financial Supervision entities, education and human resources, cultural and ethical values, supervisory strategies, financial Supervision laws and regulations, financial Supervision infrastructure, financial Supervision tools, and the design of Supervision and control procedures. The findings of this research can be utilized by policymakers and decision-makers in the field of financial oversight of public sector budgets.