This study aims to assess the effectiveness of tax mechanisms in promoting sustainable development in Saudi Arabia through a proposed quantitative framework that links core components of the tax system to financial and developmental indicators. Six key dimensions were examined: tax equity, tax certainty, regulatory clarity, convenience, database accuracy, and collection efficiency. A descriptive–analytical approach was adopted, combining theoretical foundations with field data collected through a structured questionnaire administered to three professional groups: tax authority members, external auditors, and academic researchers. A total of 185 valid responses were analyzed, supported by closed interviews conducted with selected participants to enhance data validity. Correlation and multiple regression analyses revealed statistically significant positive effects of all independent variables on financial and developmental outcomes, underscoring the strategic importance of efficient tax system design in achieving financial performance and social fairness. Non‑parametric tests further indicated significant professional differences in evaluating certain components, with academics demonstrating heightened sensitivity to equity, regulatory clarity, and administrative accuracy. The proposed framework provides an objective measurement tool that supports policymakers in refining tax strategies aligned with Saudi Arabia’s Vision 2030 goals of economic diversification, institutional efficiency, and long‑term financial sustainability.