Public budgeting is widely recognized as a primary instrument of fiscal and economic policymaking. The integration of big data can create new capacities within budgeting systems by enhancing transparency, improving forecasting accuracy, strengthening accountability, and optimizing resource allocation processes. Existing studies have identified general trends in the application of big data in budgeting systems; however, they have not comprehensively examined the challenges, opportunities, and policy guidelines related to its implementation within policymaking systems. Accordingly, this study aims to identify the challenges, solutions, and opportunities associated with the use of big data in Iran’s public budgeting system. The research adopts a qualitative approach using thematic analysis. The study population consisted of experts in public budgeting, who were selected through purposive and snowball sampling techniques. Data were collected through semi‑structured interviews, and theoretical saturation was achieved after the fifteenth interview. The collected data were organized and analyzed according to the stages of thematic analysis.
The analysis resulted in the identification of 24 main themes that explain the various dimensions of challenges, strategies for overcoming these challenges, and opportunities arising from the application of big data in Iran’s public budgeting system. The findings provide a scientific basis for policymakers and public sector managers seeking to reform budgeting processes through data‑driven approaches and to enhance financial transparency and accountability.