This study aims to propose an accounting model for measuring the cost-effectiveness of subsidy expenditures in the state budget, emphasizing its critical role in achieving social justice and environmental protection. The study adopts a deductive approach to establish a comprehensive theoretical framework through reviewing and analyzing relevant literature, scientific references, and official documents on the state budget. Additionally, a quantitative approach was employed to analyze data collected from relevant Egyptian government entities, such as the Ministry of Finance and the Central Auditing Organization, alongside surveys and interviews with experts and beneficiaries of subsidy programs. The study found that accounting information related to subsidy expenditures provides valuable insights that enhance decision-making efficiency in resource allocation and reallocation. This, in turn, fosters a balance between economic, social, and environmental objectives. Furthermore, the findings reveal that developing a quantitative model for measuring cost-effectiveness significantly improves the quality of fiscal policies, optimizes public spending, and reduces budget deficits, thereby positively contributing to sustainable development and promoting social justice.