Over the past decade, significant budget reforms have occurred in many countries, including Armenia. The research discusses the nature and forms of budget reforms and their positive impact on enhancing budget expenditure management under a sustainable development framework. Governments worldwide prioritized these reforms to improve the efficiency of public expenditure management. The research discussed the challenges faced by Armenia and highlighted the need for comprehensive reforms. Subsequently, it investigates key reforms implemented in OECD countries and compares them with those in Armenia. These reforms include the introduction of fiscal rules, a medium-term expenditure framework (MTEF), performance-based budgeting, specifying gender budgeting, evaluation mechanisms, and budget transparency, which are important for sustainable development. While Armenia has shown a commitment to improving its budget system, notable gaps still exist that the government’s future policy should address. To ensure the effectiveness of these reforms, they must be built as a package and should be sustainable․ The research presents a new definition of budget reform and concludes with recommendations for improving public expenditure management.