The research aims to analyze the impact of implementing economic reform programs on domestic public debt in Egypt during the period (1990–2023). This research aims to assess the shifts in the structure of domestic public debt and its relationship with macroeconomic variables. It tracks the evolution of the size and structure of domestic public debt during the various periods of economic reform, analyzes the impact of economic reforms on financial sustainability indicators, and analyzes the relationship between economic policies and domestic public debt. It also provides recommendations to help improve the efficiency of public debt management and achieve sustainable financial balance. The research concludes: First, it confirms the validity of the three research hypotheses. Second, the research results show that the structure of domestic public debt was characterized by shortcomings, as it relied on short-term and high-cost instruments, which contributed to its weak long-term sustainability. Third, the period (1991–2005) was characterized by the weak effectiveness of financial reforms and the persistence of structural imbalances in public finances. Meanwhile, the period (2006–2015) witnessed some improvement in transparency and growth, but without radically addressing the fiscal deficit and the dominance of debt instruments. The period (2016–2023) witnessed a relative improvement in debt management and a reduction in its ratio to GDP, while the problems of high debt costs and weak revenues persist. The study also found a direct impact of monetary and fiscal policies—particularly those of raising interest rates, reducing the general budget deficit, and liberalizing the exchange rate—on the development of domestic public debt. Finally, the study demonstrated that the state's reliance on domestic financing negatively impacted debt sustainability by crowding out the private sector and slowing economic growth. The study recommended adopting a comprehensive financial reform focused on reducing the deficit by maximizing revenues and restructuring subsidies in a fair and effective manner, It also recommended reducing reliance on short-term debt instruments, directing borrowing toward productive projects, enhancing transparency, and linking debt management to sustainable development goals.